<p><b>How to fix USB not working after installing Windows XP Professional over XP Home </b>

Press Windows Button & Pause/Break to go to the System Properties (or right click on My Computer and choose Properties, but the other way is more fun.)

Choose Device Manager.

Expand the Universal Serial Bus controllers section

Right click and choose Properties of one that says something about PCI bridge (I forget the exact name and after you fix the problem, this item goes away. If you aren't sure, you try step 5 and 6 on all of the USB items in that list.)

Click on the Driver Tab (it's kinda slow loading).

If the driver information on top says "Not found" or "Not installed" then click Update Driver... and let it look for the driver itself (I didn't need the XP CD but that might be because I keep a copy of it on my hard drive just incase. You might need it, I don't know.)

After it finds the driver, click Okay and USB should start working immediately - no reboots needed!

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