There are many times I am working on a computer and I see a "?" in the Device Manager and it says Unknown Device or something very generic like VGA Adapter. Items like that are very annoying. The way to fix this is a 2 part process. The first part is getting the hardware codes, the 2nd part is determining what they are.
Part 1 - Finding the hardware code.
- Right-click on the My Computer icon and select Manage
- Select Device Manager
- Right-click on the device in question and click Properties
- Select the Details tab
- Select Device Instance ID(Windows XP) or Hardware Ids(Windows 7) from the dropdown list
- Note the hexadecimal values after the VEN_ and DEV_
Part 2 - Determining the hardware
- Open Internet Explorer
- Go to www.pcidatabase.com
- Enter the value of the DEV_ in the Device Search field and click Search
- Review the results until you find the proper Vendor ID
By using these steps, you can figure out what an unknown device is and download the proper drivers for it.