I'm assuming you running Windows?!
If so open your device manager
- XP: Control Panel > System > Hardware Tab > Device manager
- Vista: Control Panel > System > Advanced system settings > Hardware Tab > Device manager
If your device is installed physically but without drivers, it should appear as "unknown device" ...
So find it and view its properties (right-click > properties).
If the "Details" tab, select "Device Instance ID" and/or "Hardware ID"... you should het a long alpha-numeric string that looks like this:
- VID = Vendor ID --> 046D is Logitech
- PID = Product ID --> 08DA is QuickCam Messenger
- The rest is additional info like revision, etc.
Do that and copy+paste the string here... from that you can get the manufacturer and device model.