USB Keyboard
I think all MS Office keyboards are USB and that is the problem. I seem to recall that if you got the timing right you "used to" be able to hit the F Lock (change function) on boot and then the delete key and get into the BIOS, fiddle with CMOS settings in that manner.
However many months and many MS Updates later, that functionality now seems to have disappeared and you either need the PS2 adapter (mine being lost of course - think it was a little bright green or purple plastic gadget) or an old style keyboard will do it (wife chucked that out too).
It's just another MS irritation and not insoluble by any means. My Intel PIV machine is just so slow to boot into (and out of) Win XP Pro that each attempt wastes 5 minutes. When you're busy, that is a bummer.
Think I'm about to use a program my son wrote to allow me to boot off a one GIG USB flashRom device. That should speed things up a bit. I need to get something back from his university honours degree in Engineering Science IT. Usually he just looks at me as if I'm the geek and departs laughing, saying "keep at it, you'll figure it out." I usually do - but it's such a time-waster.