I have an Inspiron 9300 that will power itself on somewhere between 5 and 7 in the morning (looking at event viewer records). Every time I hibernate it, then go to bed, it will be on when I wake up. If I actually shut it down (not hibernate), this doesn't seem to happen, and I don't think it happens when the AC adapter is not plugged in either. I do not have my BIOS set to automatically power on (I double checked), but it seems to anyway.
Any suggestions would be greatly appreciated.

Specs (if it helps):
Inspiron 9300
1GB dual channel DDR2 533MHz, Centrino 2.00 GHz, 100 GB HD
Windows XP Media Center Edition (tv tuner NOT plugged in when this happens, and no scheduled recordings)