2000 screen reaches end of bars and restarts????

:confused: I get "Windows 2000 Professional Starting" screen and when it reaches the end of the "loading" bars, the hard drive shuts down and restarts. This started happening after I downloaded an update "supposidly" from Microsoft. I did not pay attention to what the update was however. It told me to reboot after the download, thats when the problem started. Any suggestions? Thanks for any help in advance

Hit F8 during the Windows startup to get the Advanced Startup menu. From that choose Last Known Good Configuration and hit enter.

Hit F8 during startup, choose advanced and choose do not reboot on error, then post what it says at the blue screen.