Ehh... You'd probably be best off leaving the BIOS alone if you don't know what you're doing. If you want hidden features, download a program like TweakXP.
The only type of bios work that I have done is just changing the boot logo. I have seen posts on the net where people have sucessfully modded there bios and opened hidden settings. I want to play on my really old computers. So, if I screw something up, its no big loss.. Just like trying different things.