Ok, let's get some info
What was the last program you remember installing before these errors started
Was it CloneCD?
Also, do you have the latest video drivers from Nvidia for you card?
I am going to venture a guess, this may be your best route
Uninstall CloneCD and DVD XCopy
There is a good possibility they are interfering
Reboot the computer
Back in Windows
Go to Start>>run>>type in
sfc /scannow
Let system file checker completely run
Have your XP CD available just in case you need it
Afterwards, go back and try reinstall Service pack 2 for Windows
If all goes well, then this is the time you can go back and reinstall CloneCD and DVDXcopy
Make sure they are the latest versions