Visit the computer manufacturer's website and see if they have an updated chipset/motherboard driver.. If so, download and install it... There may also be other USB related drivers at the site..

If the driver installation doesn't help, it's entirely possible the motherboard is starting to fail.. A replacement of such might be possible but since it's a laptop with XP, I'll guess it's fairly old.. If that's the case, then you'll probably be better served with a new computer. Most laptops have a working lifetime of only 2 or 3 years.

Hope this helps.