|The proper way to install a USB printer usually involves FIRST installing any software/drivers from the manufacturer and THEN connecting the printer. From your post I gather you connected the USB printer and then went online to the HP site for drivers.|
I suggest you perform a Window restore to a point just prior to this issue. Read the article at the link below to learn how.
After you have the computer back working properly then go to the HP site and download any necessary software for your HP printer. Verify the printer can operate under WinXP at that time.