I haveWindows Xp and when I boot, it gets past the startup screen, but then stops at a plain blue screen. The cursor is visible, but none of the screen icons, such as the harddrive or workfolders are. I can't therefore access any work or applications! Help. Never had this problem before.

This is a new issue with a bad Mcafee update. Do you have McAfee or AOL Security Edition installed? If you do that's the reason.
The way to fix it:

System Restore from Recovery Console:
http://www.toughadmin.com/article.php?article=System

Then when you're back in windows uninstall McAfee/AOL