Well that would depend on your BIOS.
I suggest you tell us what PC and what brand of BIOS is being used. (AWARD, Phoenix etc..)
The IRQ you are looking for should be marked with the word "reserved" in the bios, when you get that far. Also, remember: Google is your friend. a quick search on google gave me the following page: DELETED where you should be able to download a specific manual for your PC. If not it problably is a HP or other brand computer and you will have to search for the answer there.
Edit:
OOPS it seems the page I directed you to was a hoax, I tried it and it directed me to porn sites instead of bios manuals. I apologize to all who tried it.
Check out this page instead:
motherboards
Best of luck
/m
