Since someone hasn't replied to your thread in a very long time I might as well attempt on helping.
I found someone who had the same problem.
Hope it helps.
A friend has a Dell system running Windows XP. He purchased the latest edition of MS Office. Before installing Office, he heard that he should run Windows Update before installing so he did. From what he can recall, the two updates that came down were for .net and a video driver and then he rebooted as instructed. Now his computer won't boot. As soon as it gets past the Dell splash screen, the screen goes black and there is just a blinking cursor. He tried coming up in Safe mode but had the same results.
He was able to boot from a recovery disk and run Windows Repair but it made no difference. Anyone have any suggestions other than format and restore?