If you plug your usb drive into a working usb slot, then it should show up in the start>computer>Devices with removable storage.
This is assuming your working with windows 7.
I would make sure the usb slot your using is working, and if it is, I would check
control panel>hardware and sound>devices and printers, there you should see everything that is plugged in to your computer, printers, mouse, keyboard etc
Check to see if it shows up in there.
When you plug and unplug that usb in, does your computer make a noise, like dun dun?