Getting in the BIOS can be tricky. Usually, pressing the DEL key about twice a second, repeatedly, after resetting, will get one in to BIOS, but sometimes it's not the DEL key, but instead, it's the F1, F2, F6, F7 key. Sometimes CONTROL + B, or CONTROL + ALT + B works.
Pause the screen when your computer boots up. Exactly what type of BIOS, and what version does it say you're using, when it boots up? This may be one such variable the previous post might need to know.
What sound drivers are you using?
I explained in previous posts, one way of finding out. Send us the info for more help.