|If the printer is printing some of the time what makes you think the USB port is a problem. If it were not working the printer wouldn't work either.|
Check out what printer is configured for use in your word processing program.
WinXP doesn't need special drivers for USB. The motherboard chip set drivers are all that is needed. As stated, USB must be working.
Explain where you determined the USB port was not working and exactly all the steps you took to fix things.