Karl;
Perform a Clean Installation.
Disconnect all peripherals (camera, printer, scanner, etc)
Go to BIOS and set CDROM as boot device before hard drive.
Insert Windows XP CD and reboot.
At "Press any key to boot to CDROM" quickly press a key and follow the
prompts for a Clean installation:
http://www.winsupersite.com/showcase/windowsxp_sg_clean.asp
Delete all partitions in step 5 if you desire to erase all data on the
hard drive.
Partitioning and formatting will be done automatically.
All data will be destroyed, back-up important data first.
After you are finished, you will need to load the appropriate drivers.
If your computer was shipped with Windows XP, these procedures may or
may not apply.
Check your manual or contact the computer manufacturer for more
details.