How to reset bios in asus pro5di motherboard

As a general rule, almost all MBs a "Clear CMOS" jumper, look for it and move it to the second position, then turn it on and check if the BIOS is back to default settings. If it is, turn it off and put the jumber back where it was originally.

Here you might find some more info: http://pcsupport.about.com/od/fixtheproblem/tp/clearcmos.htm