Unknown devices in Windows

One of my friend had an old windows pc. One fine day, he got infected with a virus and had re-install Windows thru a clean reboot. But, after completing Windows installation, most of his devices were not working. His display card was set as generic vga card, the sound card was not identified, the network card(ethernet card) was not detected..! He was almost lost hope as it was 5 year old pc and he already lost all driver cds and manuals. As a last resort, he came to me asking if I can do any thing about it.

Comments..

David(2016-05-30) : It seems this method which you have given refers to Windows xp only. Is there any method which works also for Windows 10, 8.1, or 8? I did read several methods but could not find a working one till now.

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