David;
Your problems are likely hardware related or a bad installation of
Windows XP.
If you upgraded, you probably need to perform a Clean Installation.
If you upgraded, did you make sure your computer is ready for Windows
XP (especially #3 Upgrade Advisor)
http://www.microsoft.com/windowsxp/home/howtobuy/upgrading/default.asp
You may need to power off, open case and reseat all cables and cards
to ensure a good connection.
Make sure all drivers are the latest and also compatible with Windows
XP.
If you give details as to what exactly is wrong, perhaps someone can
help, otherwise a Clean Install may be in order:
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.
