Computer hard locking when I reboot/shutdown help!

[BadAsh]

Hey guys, I am running Windows ME and whenever I choose Restart or Shut Down from the start menu my computer looks like it is going to reboot/shut down but then hard locks. The screen goes black and changes resoultion like it is going to reboot but never gets that far. Nothing is locked up in the background, I checked before shutting down. This just started yesterday btw. Anyone ever hear of this? Here is my system:

Athlon 700
MS mobo (forget #)
GeForce (Prophet DDR)
SB Live
D-Link net card
256 meg ram

Thanks