The CMOS is where your BIOS configuration information is stored. Most motherboards have two pins on them labelled "CMOS Reset" or "Clear config data" or something similar. Shorting those by touching them with a metal object (with the PC powered off) will clear the setup information.
If your not familiar with the innards of your PC, it's not something I'd advise.
You could use another PC to create the Windows XP Startup floppy disks, see here
. You will need 6
blank floppy disks.
Change your BIOS settings to boot from the floppy drive, and boot from floppy disk 1.
This would have the same effect as booting from the CD-ROM, although you will still need the CD if you intend to reinstall Windows.
What is the last driver listed when you try to boot into Safe Mode?