This is an ongoing list websites with lists of BIOS entry keys. Of course, Googling works to find these links, but there are here for one less thing to look for when you want to use WinFE
*TIP: When in doubt, you may want to first disconnect the hard drive and test the boot sequence before booting to any forensic boot OS (USB or CD/DVD).
http://pcsupport.about.com/od/fixtheproblem/a/biosaccess_pc.htm
http://pcsupport.about.com/od/fixtheproblem/a/biosaccess_mb.htm