Previously I had just completed performing this same operation on two other devices (all win7 i7s) with no problem.
To all appearances this upgrade had also succeeded. I was doing some insignificant tasks like narrowing of task tab columns in the new client when the "not responding" message appeared. I spent approximately 10 minutes a) staring balefully at the screen expecting BOINC Manager to find its way out and b) poking around in Win 7 task manager for any possible hints. When my admittedly limited reservoir of patience ran out I took the nuclear option and cancelled BOINC.
When I restarted BOINC the following tub of cyber entrails greeted me. Welcome back to 6.10.58.
_____________________________________________________
7/27/2013 2:38:57 PM Starting BOINC client version 6.10.58 for windows_x86_64
7/27/2013 2:38:57 PM log flags: file_xfer, sched_ops, task
7/27/2013 2:38:57 PM Libraries: libcurl/7.19.7 OpenSSL/0.9.8l zlib/1.2.3
7/27/2013 2:38:57 PM Data directory: C:\ProgramData\BOINC
7/27/2013 2:38:57 PM Running under account PaulB
7/27/2013 2:38:58 PM Processor: 8 GenuineIntel Intel(R) Core(TM) i7-2600 CPU @ 3.40GHz [Family 6 Model 42 Stepping 7]
7/27/2013 2:38:58 PM Processor: 256.00 KB cache
7/27/2013 2:38:58 PM Processor features: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss htt tm pni ssse3 cx16 sse4_1 sse4_2 nx lm vmx smx tm2 popcnt aes pbe
7/27/2013 2:38:58 PM OS: Microsoft Windows 7: Home Premium x64 Edition, Service Pack 1, (06.01.7601.00)
7/27/2013 2:38:58 PM Memory: 15.98 GB physical, 31.97 GB virtual
7/27/2013 2:38:58 PM Disk: 1.82 TB total, 1.76 TB free
7/27/2013 2:38:58 PM Local time is UTC -7 hours
7/27/2013 2:38:58 PM NVIDIA GPU 0: GeForce GT 430 (driver version 31422, CUDA version 5000, compute capability 2.1, 2048MB, 179 GFLOPS peak)
7/27/2013 2:38:58 PM World Community Grid [error] State file error: missing application file wcgrid_dsfl_vina_6.25_windows_intelx86
7/27/2013 2:38:58 PM World Community Grid [error] State file error: missing application file wcgrid_gfam_vina_6.12_windows_intelx86
7/27/2013 2:38:58 PM World Community Grid [error] State file error: missing application file wcgrid_sn2s_vina_6.20_windows_intelx86
7/27/2013 2:38:58 PM World Community Grid [error] State file error: missing application file wcgrid_gfam_vina_6.12_windows_x86_64
7/27/2013 2:38:58 PM World Community Grid [error] State file error: missing application file wcgrid_dsfl_vina_6.25_windows_x86_64
7/27/2013 2:38:58 PM World Community Grid [error] State file error: missing application file wcgrid_sn2s_vina_6.20_windows_x86_64
7/27/2013 2:38:58 PM World Community Grid [error] State file error: missing application file wcg_hpf2_rosetta_6.40_windows_intelx86
7/27/2013 2:38:58 PM World Community Grid [error] State file error: missing application file wcg_hfcc_autodock_6.40_windows_intelx86
7/27/2013 2:38:58 PM World Community Grid [error] State file error: missing application file wcgrid_cep2_6.40_windows_intelx86
7/27/2013 2:38:58 PM World Community Grid [error] State file error: missing application file wcg_hcc1_img_7.05_windows_intelx86
7/27/2013 2:38:58 PM World Community Grid [error] State file error: missing application file wcg_hcc1_img_7.05_windows_intelx86__nvidia_hcc1
7/27/2013 2:38:58 PM World Community Grid [error] State file error: missing application file wcgrid_faah_7.15_windows_x86_64
7/27/2013 2:38:58 PM World Community Grid [error] State file error: missing application file wcgrid_faah_7.15_windows_intelx86
7/27/2013 2:38:58 PM World Community Grid [error] State file error: missing application file wcgrid_fahv_vina_7.06_windows_intelx86
7/27/2013 2:38:58 PM World Community Grid [error] State file error: missing application file wcgrid_fahv_vina_7.06_windows_x86_64
7/27/2013 2:38:58 PM World Community Grid [error] State file error: missing file faah44069_ZINC11948929_xPR_wC6_11_1ref9_01_AD4.1_bound.dat.gzb
7/27/2013 2:38:58 PM World Community Grid [error] State file error: missing input file faah44069_ZINC11948929_xPR_wC6_11_1ref9_01_AD4.1_bound.dat.gzb
7/27/2013 2:38:58 PM World Community Grid [error] Can't handle workunit in state file
7/27/2013 2:38:58 PM World Community Grid [error] State file error: missing file faah44070_ZINC03392939_xPR_wC6_11_1ref9_01_AD4.1_bound.dat.gzb
7/27/2013 2:38:58 PM World Community Grid [error] State file error: missing input file faah44070_ZINC03392939_xPR_wC6_11_1ref9_01_AD4.1_bound.dat.gzb
7/27/2013 2:38:58 PM World Community Grid [error] Can't handle workunit in state file
7/27/2013 2:38:58 PM World Community Grid [error] State file error: missing file faah44076_ZINC40009577_xPR_wC6_11_1ref9_02_AD4.1_bound.dat.gzb
7/27/2013 2:38:58 PM World Community Grid [error] State file error: missing input file faah44076_ZINC40009577_xPR_wC6_11_1ref9_02_AD4.1_bound.dat.gzb
7/27/2013 2:38:58 PM World Community Grid [error] Can't handle workunit in state file
7/27/2013 2:38:58 PM World Community Grid [error] State file error: missing file faah44078_ZINC32900601_xPR_wC6_11_1ref9_01_AD4.1_bound.dat.gzb
7/27/2013 2:38:58 PM World Community Grid [error] State file error: missing input file faah44078_ZINC32900601_xPR_wC6_11_1ref9_01_AD4.1_bound.dat.gzb
7/27/2013 2:38:58 PM World Community Grid [error] Can't handle workunit in state file
7/27/2013 2:38:58 PM World Community Grid [error] State file error: missing file fahv.x3NF6_A_IN_LEDGF.pdbqt
7/27/2013 2:38:58 PM World Community Grid [error] State file error: missing input file fahv.x3NF6_A_IN_LEDGF.pdbqt
7/27/2013 2:38:58 PM World Community Grid [error] Can't handle workunit in state file
7/27/2013 2:38:58 PM World Community Grid [error] State file error: missing file fahv.x3NF6_A_IN_LEDGF.pdbqt
7/27/2013 2:38:58 PM World Community Grid [error] State file error: missing input file fahv.x3NF6_A_IN_LEDGF.pdbqt
7/27/2013 2:38:58 PM World Community Grid [error] Can't handle workunit in state file
7/27/2013 2:38:58 PM World Community Grid [error] State file error: missing file fahv.x3NF6_A_IN_LEDGF.pdbqt
7/27/2013 2:38:58 PM World Community Grid [error] State file error: missing input file fahv.x3NF6_A_IN_LEDGF.pdbqt
7/27/2013 2:38:58 PM World Community Grid [error] Can't handle workunit in state file
7/27/2013 2:38:58 PM World Community Grid [error] State file error: missing file fahv.x3NF6_A_IN_LEDGF.pdbqt
7/27/2013 2:38:58 PM World Community Grid [error] State file error: missing input file fahv.x3NF6_A_IN_LEDGF.pdbqt
7/27/2013 2:38:58 PM World Community Grid [error] Can't handle workunit in state file
____________________________________________________

.... many more state file related errors

7/27/2013 2:38:58 PM World Community Grid [error] project file refers to non-existent c4cw_00_v01.gif
7/27/2013 2:38:58 PM World Community Grid [error] project file refers to non-existent c4cw_01_v01.png
7/27/2013 2:38:58 PM World Community Grid [error] project file refers to non-existent c4cw_02_v01.png
7/27/2013 2:38:58 PM World Community Grid [error] project file refers to non-existent c4cw_03_v01.png
7/27/2013 2:38:58 PM World Community Grid [error] project file refers to non-existent c4cw_04_v01.png
7/27/2013 2:38:58 PM World Community Grid [error] project file refers to non-existent c4cw_05_v01.png
7/27/2013 2:38:58 PM World Community Grid [error] project file refers to non-existent c4cw_06_v01.png
7/27/2013 2:38:58 PM World Community Grid [error] project file refers to non-existent cep2_00_v01.gif
7/27/2013 2:38:58 PM World Community Grid [error] project file refers to non-existent cep2_01_v01.gif
7/27/2013 2:38:58 PM World Community Grid [error] project file refers to non-existent cep2_02_v01.png
7/27/2013 2:38:58 PM World Community Grid [error] project file refers to non-existent cep2_03_v02.png
7/27/2013 2:38:58 PM World Community Grid [error] project file refers to non-existent cep2_04_v01.gif
7/27/2013 2:38:58 PM World Community Grid [error] project file refers to non-existent cep2_05_v01.png
7/27/2013 2:38:58 PM World Community Grid [error] project file refers to non-existent cep2_06_v01.gif
7/27/2013 2:38:58 PM World Community Grid [error] project file refers to non-existent cep2_07_v01.gif
____________________________________________

... now messages from the regression to 6.10.58
___________________________________________________

7/27/2013 2:38:58 PM Version change (7.0.64 -> 6.10.58)
7/27/2013 2:38:58 PM World Community Grid URL http://www.worldcommunitygrid.org/; Computer ID 2061483; resource share 100
7/27/2013 2:38:58 PM World Community Grid General prefs: from World Community Grid (last modified 20-Jun-2013 20:12:33)
7/27/2013 2:38:58 PM World Community Grid Host location: none
7/27/2013 2:38:58 PM World Community Grid General prefs: using your defaults
7/27/2013 2:38:58 PM Reading preferences override file
7/27/2013 2:38:58 PM Preferences:
7/27/2013 2:38:58 PM max memory usage when active: 12275.34MB
7/27/2013 2:38:58 PM max memory usage when idle: 15548.76MB
7/27/2013 2:38:58 PM max disk usage: 10.00GB
7/27/2013 2:38:58 PM don't use GPU while active
7/27/2013 2:38:58 PM (to change preferences, visit the web site of an attached project, or select Preferences in the Manager)
7/27/2013 2:38:58 PM Not using a proxy
7/27/2013 2:38:58 PM Running CPU benchmarks
7/27/2013 2:38:58 PM Suspending computation - running CPU benchmarks
7/27/2013 2:39:29 PM Benchmark results:
7/27/2013 2:39:29 PM Number of CPUs: 8
7/27/2013 2:39:29 PM 3268 floating point MIPS (Whetstone) per CPU
7/27/2013 2:39:29 PM 8873 integer MIPS (Dhrystone) per CPU
7/27/2013 2:40:59 PM World Community Grid Sending scheduler request: To fetch work.
7/27/2013 2:40:59 PM World Community Grid Requesting new tasks for CPU
7/27/2013 2:41:02 PM World Community Grid Scheduler request completed: got 15 new tasks
7/27/2013 2:41:02 PM World Community Grid Message from server: Resent lost task faah44069_ZINC11948929_xPR_wC6_11_1ref9_01_0
7/27/2013 2:41:02 PM World Community Grid Message from server: Resent lost task faah44070_ZINC03392939_xPR_wC6_11_1ref9_01_0
7/27/2013 2:41:02 PM World Community Grid Message from server: Resent lost task faah44076_ZINC40009577_xPR_wC6_11_1ref9_02_0
7/27/2013 2:41:02 PM World Community Grid Message from server: Resent lost task faah44078_ZINC32900601_xPR_wC6_11_1ref9_01_0
7/27/2013 2:41:02 PM World Community Grid Message from server: Resent lost task faah44081_ZINC43880730_xPR_wC6_11_1ref9_00_0
7/27/2013 2:41:02 PM World Community Grid Message from server: Resent lost task faah44087_ZINC12936549_xPR_wC6_11_1ref9_04_0
7/27/2013 2:41:02 PM World Community Grid Message from server: Resent lost task faah44087_ZINC13101858_xPR_wC6_11_1ref9_01_0
7/27/2013 2:41:02 PM World Community Grid Message from server: Resent lost task faah44087_ZINC29456627_xPR_wC6_11_1ref9_01_0
7/27/2013 2:41:02 PM World Community Grid Message from server: Resent lost task faah44126_ZINC29248347_xPR_wC6_11_1ref9_03_0
7/27/2013 2:41:02 PM World Community Grid Message from server: Resent lost task faah44127_ZINC06012354_xPR_wC6_11_1ref9_01_0
7/27/2013 2:41:02 PM World Community Grid Message from server: Resent lost task faah44127_ZINC37868771_xPR_wC6_11_1ref9_01_0
7/27/2013 2:41:02 PM World Community Grid Message from server: Resent lost task faah44128_ZINC03323458_xPR_wC6_11_1ref9_00_0
7/27/2013 2:41:02 PM World Community Grid Message from server: Resent lost task FAHV_x3NF6_A_IN_LEDGF_0049890_0353_0
7/27/2013 2:41:02 PM World Community Grid Message from server: Resent lost task FAHV_x3NF6_A_IN_LEDGF_0049900_0496_0
7/27/2013 2:41:02 PM World Community Grid Message from server: Resent lost task FAHV_x3NF6_A_IN_LEDGF_0049911_0755_0
7/27/2013 2:41:04 PM World Community Grid File wcgrid_faah_7.15_windows_x86_64 exists already, skipping download
7/27/2013 2:41:04 PM World Community Grid File wcgrid_faah_graphics_prod_64.exe.7.15 exists already, skipping download
7/27/2013 2:41:05 PM World Community Grid File faah_image01_7.15.tga exists already, skipping download
7/27/2013 2:41:05 PM World Community Grid File wcgrid_fahv_vina_7.06_windows_x86_64 exists already, skipping download
7/27/2013 2:41:05 PM World Community Grid File wcgrid_fahv_vina_prod_64.exe.7.06 exists already, skipping download
7/27/2013 2:41:05 PM World Community Grid File wcgrid_fahv_graphics_prod_64.exe.7.06 exists already, skipping download
7/27/2013 2:41:05 PM World Community Grid File fahv_image01_7.06.tga exists already, skipping download
7/27/2013 2:41:05 PM World Community Grid File fahv_image02_7.06.tga exists already, skipping download
________________________________________________

I guess my present need is a recommended path back to v7.

Thanks
Paul