What is a BIOS Virus?
Are they preventable? (besides having an AV scanner)
Are they common, or were they at one time?
Are new computers exposed to them?
What damage do they cause?
Is it difficult to make a program or malicious code that can access the BIOS?

A bit questioning today - Zylstra555http://www.google.com/search?hl=en&q=BIOS+virus

I don't think so.You're probably thinking of a BOOT sector virus...not as common as they used to be but are going through a resurgence as the newest batch of malicious idiots are cutting their chops in the malware world.
They are particularly hard to get rid of and usually need a floppy based AV to sniff them out and remove them or a complete low-level FORMAT and re-partitioning of a HDD in extreme cases.Quote

You're probably thinking of a boot sector virus...not as common as they used to be but are going through a resurgence as the newest batch of malicious idiots are cutting their chops in the malware world.
They are particularly hard to get rid of and usually need a floppy based AV to sniff them out and remove them or a complete low-level format and re-partitioning of a HDD in extreme cases.

No, not thinking of an MBR virus.
(Easy fix for those since I had a problem with a Windows 3.0 instalation disk at one point:
fdisk /mbr
re-writes the Master Boot Record. It can even clear a program like Lilo, so it can be problamatic)
After my research, (From GX1_Man's link to Google), I found out that they do exist, and that they can be quite dammaging.
I had an uncle who said at one time a long time ago that he had a BIOS virus, and I wanted to do more research on it some day. (now I know)
The BIOS are infected through the BIOS Updates (which, on many BIOS chips, can be dissabled to prevent such a virus)