Digital Signature Errors

I upgraded a desktop and laptop from Vista Ultimate to Win 7 RC and have the same problem on both. I can't install programs, run msconfig, cmd, regedit, etc, because I receive a digital signature error that is supposedly related to a recent hardware or software change. I can't even edit the properties of the accounts because of this same error.

Interestingly enough on my laptop one account shows a blank programs list when you go to start-all programs, but on the other account they show up. I restored the desktop from my windows home server and will shortly do the same on the laptop if I can't figure out this problem.

Any ideas?

I was really trying to avoid that. I don't mind reinstalling programs, but I didn't want to risk losing any of my Outlook data. If many people have similar issues doing upgrades when Win7 goes public MS will have another nightmare on their hands.

Why don't you just backup your pst file? It's what I do when I re-install Windows.

Thanks for the advice and I use the .pst backup tool. I have restored from it before and found it to be a little incomplete. I will probably download the .iso again and try a fresh install when possible.