If you have an XP disk and the driver disks, that would seem to be your best option at this point.
I agree with the suggestion for a clean install. The thing most people don’t realize is that hard disks have errors, and when they get old enough, the data on them gets corrupted. Eventually some operating system file gets corrupted, and things stop working. In later versions of Windows, Microsoft introduced a feature that keeps a backup copy of operating system files, and a utility, System File Checker (sfc.exe), that can detect and correct corrupted OS files. But because you are on XP, that isn’t an option.
So back up everything important and do the clean install.