Step 1. Open device manager by typing Devmgmt.msc at run.
Step 2. Right mouse click on the unknown device and select properties.
Step 3. On the device properties window click on the Details tab and select Hardware Ids.
Step 4. Here you only need to note down these two information highlighted in the rectangle shown in the above picture-18(a).So as shown in the picture above note down VEN( Vendor ID) -168C ( as shown in the above picture) and DEV ( Part/Device ID )- 0032 as per the above picture.
Step 5. Go to website http://www.pcidatabase.com/ and then under vendor search Type the Vendor ID as 168C or whatever it shows in your device properties windows for that unknown hardware, and then hit search.
Step 6. Now you will see the result on a different page with the name of the Vendor so Click on the Vendor name as shown in the picture -18(c) and then it will show you the list of all the device available from that vendor.
Step 7. so you will need to find the device with code mentioned in the Hardware Ids as DEV which is 0032 in my case.
Step 8. Now here it clearly shows you the name and model of the device we were looking for with the link to find the driver of this device under Notes so you can probably go to that vendors website to download the driver for that particular Device Model which is installed in yourPC.For a detailed information on this topic visit my post http://bookingtohosting.blogspot.in/2014/05/identify-hardware-installed-in-your.html
Thanks for posting, I have a guide here which covers some of the steps you have brought up:
I have focused mainly with Dell hardware variants for instance Dell wireless cards because Dell usually have multiple per system.
The PCI database is very useful but I find it doesn't list everything. I made this suggestion on IdeaStorm for a Dell Hardware ID database: