Hello joneill003,
I am a single user, but here is what I just did on my own computer. I went into 'My Computer' and clicked on 'Documents and Settings' on my C drive. Then I clicked on my subdirectory, then 'Start Menu' - 'Programs. I right-clicked on World Community Grid, selected Cut, then I clicked on 'All Users' at the top and went down to the corresponding spot, where i right-clicked and pasted World Community Grid. Then I went back to my own subdirectory and clicked on 'Startup'. I cut the WCG shortcut from my Startup directory, then I pasted it into the 'All Users' Startup directory.

My security programs were warning me that something was fooling with my startup settings, so I reassured them. I think that was all I needed to do, but just to be sure, I rebooted.

Everything is running fine. Even better is to run as a service, so you do not exit the program even when switching users. It is more complicated to set up, though. The instructions are at http://www.unofficialworldcommunitygrid.com/service.shtml

Hope this helps. Ask if anything is not clear.
mycrofth