I have an IBM TP R51 that's acting a little funky.

If i try to boot up the laptop with the AC adapter plugged in, the hard drive starts spinning, but the screen stays blank, nothing comes up.

If i remove the AC adapter and perform a hard reboot, then it's fine, when i see the windows XP screen i can put the AC adapter back in place and everything is normal from then on.

This has been happening for a week now. Does anyone have any ideas?

Thats strange, sounds like it could be a problem with the AC adapter. Try another adapter. Sorry don't have much more to suggest. Anybody else have a suggestion?