Check out the disclaimer for a certain MB...
ASUS A7V Issues
1.Your CPU temperature should be lower than 60C
2.Your BIOS version must be 1003 or 1004A (recommended)
3.Diamond MX300 and Aureal 3D Sound Card are not compatible with A7V
4.AGP setting must be matched with your Video Card. (2x or 4x)
5.Try Normal setting not Optimal setting in the BIOS.
6.Try manual setting for CPU speed.
7.Install VIA 4-in-1 driver.
8.Download latest driver for Promise controller from
www.asus.com.tw/products/motherboard/socketA/a7v/index.html
9.Put your Sound Card in 3rd PCI slot.
10. Look up at the stars and wait for jupiter to cross the orion constellation.
...and don't forget to toss a handful of salt over your shoulder and repeat 21 hail mary's before turning on computer!