Help with an Abit ah6 please

[FredlyFX]

My friend is trying to use an ah6 he got from me. I had already flashed the bios with the latest ones. He has a celeron 533 he is trying to use. When I had it I was using a pci vid card, and he has put a voodoo3 agp in it. The problem is that when he goes into the bios he can only work with it for about a minute or less before it starts giving him blue lines across the screen so he can't see anything. Any ideas? This mobo was working great for me with a 266 in it.

Thanks

FredlyFX