How do I get my USB ports to recognize devices?

[Specs]

My computer is a Dell Inspiron N5030, running Windows 7. Every time I plug something into a USB port, it says "USB Device Not Recognized." It happens no matter what I plug into the USB port (I've tried a wireless mouse, an iPod, and an external hard drive). At first it was just one port, now it's both.

I tried uninstalling all the USB Host Controllers and restarting the computer so they'd reinstall, but it didn't work. I've had this problem once before on the same computer, and that worked, but not this time. I've tried searching for new drivers for all the devices (even though I've never had to use drives for them before), but none are ever found.

Does anyone know of another solution I could try?