External Harddrive has reserved two USB ports

I've bought a new external hard-drive and it needed formatting. It took twelve hours to format and when it eventually finished, I've found that none of my other USB devices work in the front two USB ports. I've tried my iPod, my memory stick and even my USB mobile phone cable. It simply doesnt work. The computer doesnt detect it and i recieve no alerts or messages whatsoever - it simply doesnt work. All my other devices, however, work with the USB ports at the BACK of my computer. The only thing that works in the front two USB ports is my external hard-drive, which leads me to believe that it has reserved those two slots for itself.

I've tried uninstalling the drivers and re-installing them, but to no avail.

Any help would be greatly appreciated. Thanks!

I'm not sure, the USB Ports have been working perfectly fine previously, and the fact that it took 12 hours for my external harddrive to format isnt neccesarily the main concern for me - the main thing that boggles my mind is the fact that the front two ports only detects the external harddrive, nothing else. Every other device only seems to work in the ports located at the back of the computer.

Also, i've tried the external harddrive in two other computers and it works fine - I also tried using my other USB devices (memory stick, iPod) into them to see if the extrenal hard-drive 'reserved' the USB ports again - but no, the USB ports works fine with everything. The problem only lies with my main computer.

The external hard-drive is 1 TB