iPod
It sounds more like an OS problem to me, especially after searching the problem. Seems that a lot of people have this issue, usually due to driver problems or other software.
Which iPod are you using?
Vista has always been pretty temperamental towards ext devices, so you may want to expect problems like this in the future.
When you plug the device in do you get a message asking about drivers? Have you installed any new programs recently? Did your iPod work before they were installed?
How many USB devices are you using? You may be using too many for the iPod to work properly. If you use a lot of the USB's on your laptop, unplug a few devices and then retry your iPod. Does it work now?
Have you tried any other devices in the USB slot? If other devices dont work may be a hardware issue with the socket. (eg: broken, loose wiring, dirty, etc...).
Also, are you having any other problems with your computer? Have you ever dropped it or has it ever been banged around? Also consider who you got the computer from, do you think they were careful with it?
When was the last time you restarted your laptop? That can help in certain cases.