I encountered the following problem:
On my DH55TC, I had an external USB audio device connected to one of the rear USB ports. Suddenly while listening to music, the USB audio device stopped working. It also disappeared from the list of known devices. I connected this device to another USB port and also to another computer -- the device works fine.
Next, I connected several devices to that specific rear USB port -- none of them is recognized. With one of my USB flash drives I noticed that the LED lights up as soon as I stick it into this USB port. With all other ports, the LED just flashes once when the device is connected and it is recognized immediately as a storage device.
It seems to me that the specific USB port is defective -- there is power but no data connection. But how can this be? All other ports still work fine.
I don't think it's a driver issue. I connected a USB flash drive to different ports and went into the boot device manager at startup. Only on this one rear port the device is not shown.
Having one defective port is not a big problem as there are enough others. My concern is: How can I be sure that there are no other defects (coming up soon)?
Should I replace the board (I'd have to check if it is still under warranty)?
In this kind of cases, it will be a good idea to get the latest updates on the board (drivers and BIOS ) and operating system like Service Packs and check results after that. If still not working we may be facing an isolated problem in one of the USB ports, but if you are concern on the product stability on the near future, give it a try with the updates and if the problem continues check the warranty with the place of purchase and let them know about the issue your are having.