How to restore a Windows 7 PC without Serial Number on Case?

Question

I am more of a software developer/programmer then a hardware/computer tech person but I can still build my own PC's and fix them, it's just not something I do for other people too often.

With that said, I have a lot of people frequently coming to me wanting me to fix there computers which are usually filled with virus and just a bunch of garbage. I Know there are many scanner programs to help detect and remove this stuff but I am a firm believer that it is generally better to just wipe the drive and start with a fresh install of Windows and everything else.

If I am doing this on my own PC's I know that I purchased Windows 7 and I have my own serial numbers for my own use. The problem I am facing is a lot of people who come to me will have a laptop or desktop that came with Windows XP installed so the serial number found on there case is usually for those computers but they at some time had Windows 7 installed. If I tell them I will have to install Windows XP, they aren't going to be happy with that and often they don't have the Windows 7 serial as someone else had previously installed it for them.

Is there anything can do to install windows 7 on a PC that already has Windows 7 but does not have the serial number on the case or in there possession? What are my options to make the client happy?

Sorry if this seems like a dumb question but it is one I have had for several years, I usually turn away work because I am not sure how o handle this for people. I would hate to tell them the only solution is to purchase another copy of Windows 7 and have them tell me, "well the other guy installed it for me without a problem"

Answer 1

First download the appropriate ISO from the Microsoft servers and then use Magic Jelly Bean to find their serial number. Note that if their version of Windows is cracked or Volume Licensing then this will not work.

You can then reinstall Windows via the disk and use the serial key shown in the Keyfinder. Also, even with the Microsoft ISO if you don't have the serial number you will not have a legitimate version of Windows, so make sure you have the serial before you format their computer.

Another thing you could do is ask them if they would like to upgrade them to Windows 8. It is cheap until the 31st and you can do a clean install with upgrade media anyway.