computer can't recognize devices?

My mother has a 5 year old Toshiba Satellite Laptop that habitually finds new problems. The most recent issue invovles the USB ports.

We attempted to connect a sansa MP3 player to add music. The computer did not show the device in My Computer. We wiped the harddrive a while ago so we reinstalled the software that came with the MP3 player. The machine stil does not recognize that anything is plugged in. The MP3 device shows that it is plugged in and connected.

It has had the same problem with other usb devices including speakers. It makes a "donk" noise when you plug in the cable so I think some part of the computer knows that theres a device but we cannot access it.

How bad is this? Is there anything we can do to fix it or test it?

Thanks!