Mmmmm...maybe I could help you. But i need you to answer a few questions first. First of all, does your system POST? (And by that i mean boot up, showing the motherboard logo ect). If so, start up the PC, and when the PC is 'POSTING' and the motherboard logo has appeared, press either 'Delete' of 'F1' to enter your BIOS, (it differs on each motherboard). When the BIOS screen has loaded, press the correct key to restore the default settings. It's usually 'F5' on Asus motherboards. Apply your changes and reboot. Now Im assuming your PC boots, or half boots ito windows, before it screws up, so if the first solution doesn't work, press 'F8' to load the boot menu, and boot with safemode. Reverse, delete or restore any hardware program changes ect.... If that does't work, you might have to reset the CMOS switch on your motherboard. Don't try this if your unsure of what you are doing ect. Resetting the CMOS is straight forward, you just have to be carefull of static electricity. To do this, remove the side of your PC (after switching it off at the wall!!), and locate the CMOS jumper on your motherboard. If you can't find it straight away, look for the word CMOS on your motherboard. Remove the jumper, then replace it back to it's default position after 5 secconds-ish. The power on, and reboot your PC. Resetting the CMOS switch basicly forces the BIOS and hardware configs back to their default settings, so if it was being caused by a driver fault, then it should be fixed.
If all the above fails, then it's probably a hardware fault/falliure such as your processor, or a RAM conflict. You then need to contact your system builder for further details.
Hope everything works out ok
Good Luck
-Creator of zombies-