So your problem is that your iPod will not appear in iTunes correct? Have you tried a hard reset with the device still connected to a USB port directly on your PC? To do this, press and hold both the Select (Center) and Menu buttons together long enough for the Apple logo to appear.
If still no luck, try another USB port and/or sync cable if you have one on hand. There is a small chance that if you have other devices plugged into your other USB ports, that there is a device conflict. To eliminate this possibility, remove all other USB devices (minus the keyboard and mouse) and reconnect your iPod after rebooting your PC.
Otherwise, continue the troubleshooting mentioned in this Apple support document as necessary.