First, before you go to all this trouble, it probably hung due to memory. So put in your new memory, put in the XP cd, and boot from the cd and you should be ok. That's the way things are supposed to work.
Make sure your memory is approved by Gigabyte - it's a fussy board.
If you still have problems, go to the Western Digital site and download a formatting utility, and a Hdd fitness testing utility just for kicks. Both run on floppies. The CD version never worked well for me. Run the HDD test first, and if your Hdd passes, then do the formatting with the Western Digital floppy. It only takes a few seconds, as I remember, and you can partition and get all of your 160 gigs minus a few gigs "overhead" used by the NTFS file system.
Let get running before you worry about the BIOS.
Usually near the battery is a set of three pins with a jumper covering two pins. It may be marked on the board as "clear cmos" or just "cmos". The pins are side by side. For example if pin one and two are covered, move the little plastic jumper to pin two and three for a couple of seconds, then move it back where it was. That's all there is to it.