OC creates invisible Hard Drive

When ever I overclock my computer anywhere passed its original 800FSB the hard drive dissapears and I cant boot up. I have a P4 2.4c 800FSB with a Raptor HD. Any advice would be appreciated. THANKS

is the PCI speed locked on that board? that's the only thing that would make sense...a touchy sata controller that doens't like speeds higher than stock

Intel MB's have the AGP/PCI Mhz locked...and have you replaced the IDE cable to rule out a bad cable?

What to you mean by the PCI locked. I am not too good with computers. How can I unlock it? also my HD does work so the cable is good. And I have an abit IC7 mobo. Thanks for your guys help

He's refering to the speed that the PCI bus is set to run at in your BIOS settings. The standard speed is 33Mhz. When you increase the FSB however the PCI bus speed will also increase. However, your Abit board should allow you to lock your PCI speed so that it doesn't increase when you up the FSB. This may or not solve the problem but it is worth a try since it is so easy to change in BIOS.