Go into the Device Manager, find all the devices with a yellow question mark/exclamation point on them, double click the device, go to the details tab, then select Hardware Ids. You'll see a bunch of weird codes. For instance, a PCI device would come up with some code like PCI\VEN_3424&DEV_3242&SUBSYS_5425232. This is a Vendor code, and a device code for that hardware. If you google the string, atleast to the end of the DEV code, you should get some results, as to what drivers are needed for that hardware.
I suppose I can do a real world example:
I have a NIC, with a hardware Ids of
Code:
PCI\VEN_1814&DEV_0601&SUBSYS_28601814&REV_00
. I google that and get nothing. I then delete much of the stuff at the end, and google:
Code:
PCI\VEN_1814&DEV_0601
The first site is from drivershq.com, and it says the driver for Ralink PCI RT 2760 2790 2860 2890 wireless NIC will work for my hardware. I can then go to Ralinks website and download the dirver. However, I go there, and see that there's different drivers for their 2760/2790, and 2860/2890. If I go back and look that that hardware Ids, I'll see under the SUBSYS string, that it says 2860. I don't think that's a coincidence, so I go and download the 2860 drivers.
Keep in mind that your hardware might be mentioned in some forums, that come up as search results. These results can be useful, and you shouldn't discount them when doing this procedure.