I had been overclocking a Celeron 566 to 850 in an Asus CUBX without any problems until I installed a new hard drive, a WD 205BA UDA 66. Now Windows locks up right after booting. Currently using a 250W psu, have a 300W on order in case that is the problem. I am also wondering if switching the I/O voltage setting jumper on the board to 3.6V from default 3.45V would help. Don't want to try this without advice though. Thanks for any information.