PLEASE HELP!! - Win2K hanging up during start up!

I have a laptop that is running Windows 2000 Professional. It is one that I got from an old job when they were going out of business. Right now, it stops halfway through its boot up process - right when the Windows 2K Professional logo is on the screen and the status bar is halfway blue. Any ideas as to why it would be doing this? I've tried shutting it down and restarting, doesn't work. Should I reinstall Win2K? If I were to reinstall it, how would I do that? I tried upgrading one of my other PC's once from 98 to 2K and ended up with 2 versions on my PC - wasn't pretty. I would love to do a "fresh" install and get rid of all my old companies crap that is on it now. Can anyone help me? I'm not very knowledgeable about this stuff, but I follow directions like a champ!

Thanks in advance,
Joy

Try booting into safe mode (tap the F8 key during the startup).

If you can't get into safe mode you can repair your OS by booting from the Windows installation CD and following the appropriate repair prompts.

Doug - Tried booting in safe mode, and it hangs up in the same place. I've tried booting up with the CD, with no success. It gets stuck in the same place. Some suggested that I may have the "Sasser" worm. They told me what to download to fix it, but that is only if I get it to boot up. I just can't get it to boot up. Any other suggestions??

Thanks,
Joy