If you drill into the ca-bundle.crt file, you'll see there are quite a lot of certificates included, which is why it's called a bundle. There's certificates in there valid through 2034 if I remember correctly. Open it with wordpad and you'll see the whole content such as certs by Thawte. Coincidence the one expiring at 2009 sits at top I suppose.

Now another [redundant] question. Where again is the ca-bundle.crt? It was noted before in this thread where Lawrence's was and on my 7.0.31 running 64 bit host it's in C:\Program Files\BOINC. Got no copy in the data dir. The security properties say that boinc_project, boinc_admins, Administrators, Authenticated Users, SYSTEM have access of some form [mostly read only].

Edit: For good measure I ran the Install Certificates from the ca-bundle.crt window, then renamed the .crt file to .crtold to see effect and got instant error messages of transient fails. [Installs made no difference].

12853 World Community Grid 11-9-2012 8:10:06 Temporarily failed download of X0930067890959200605041549_X0930067890959200605041549.jp2: transient HTTP error
12854 World Community Grid 11-9-2012 8:10:06 Backing off 3 min 19 sec on download of X0930067890959200605041549_X0930067890959200605041549.jp2
12855 World Community Grid 11-9-2012 8:10:06 Temporarily failed download of X0930067890943200605041549_X0930067890943200605041549.jp2: transient HTTP error
12856 World Community Grid 11-9-2012 8:10:06 Backing off 2 min 29 sec on download of X0930067890943200605041549_X0930067890943200605041549.jp2
12857 11-9-2012 8:10:09 Internet access OK - project servers may be temporarily down.

Renamed the .crt file back, hit retry now on downloads and they came down fine.