Reinstalling My Windows

There so many reason to reinstalling operating system, like computer attacked by virus, windows error and other. Like mine was attacked virus and its can heal or deleted. So must reinstall my windows.
Reinstall windows to recovery my computer i just following this instructions.

You need the Windows Xp and CD Rom.
Star the PC,
enter in the bios pushing "del" button from the keyboard
change the boot sequence (first boot device CD Rom).
At this point save,
exit the bios,
insert the CD and restart the PC

And now my computer was OK again