Recently my dad inserted a USB plug the wrong way round which caused both our USB ports to stop working. The power light on our USB modem no longer lit so it seems likely to be a short. I bought a PCI add on with 3 USB ports having been advised this should work. On booting the PC the new hardware was not detected and I couldn't install the software manually as it told me there was no new hardware. My question is whether the short could have damaged the PCI function. I read another forum on this site that suggested it may be necessary to disable the old USB ports in BIOS and enable the PCI ones. There are a couple of USB entries in device manager which say they are working properly but I imagine that's the old ports and that the short has not been detected. Any advice would be much appreciated... Thanks

The question whether the short could have damaged the PCI function. Ans: NO As to disable the old USB ports in BIOS, should have NO impact, however it couldn't hurt since they apparently don't work anyway. There is nothing to enable regarding PCI, so I would: 1. Remove the PCI card and reinsert it. Perhaps it's not making good contact 2. If that doesn't work, insert it it into a different PCI slot, if you have one 3. Can you try it in another PC? 4. Finally, there is always the remote possibiility that the card is defective. Good luck. I - Sandor J Sound judgement, with discernment, is the best of seers. - Euripides (B.C. 480 - 406)

Thanks for the response. There is another PCI slot available but it was a bit of a squeeze to get it into the first one, so I'm going to let a friend have a look so I don't mess it up. Someone said if the 5v power supply is damaged we may need to replace the motherboard. Is that a bit too drastic? Thanks

If your power supply were damaged in any way, you'd have a lot more problems besides USB not working. Most likely your system would be not working. I - Sandor J Knowledge is the treasure, but judgment is the treasurer of the wise man. - William Penn (1614 - 1718)