Try USB at back of PC

Have you tried external HD with USB at back of your PC?

I have an external HD enclosure, which is not working if I connect to PC's front USB. However, it works flawlessly when it's connected to USB at back of PC. I think it's due to USB 2.0's higher requirement for connection. My front USB works well with USB 1.1 devices. Due to longer wire from front USB to mother board, it's not suitable to USB 2.0. On the other hand, the back USB is very close to mother board, so it has no problem.

Mouse and game port are USB 1.1 devices.