Currently i have Windows 7 (OEM) which disallows use in another motherboard. If I install a different os (win 7 or 8) will it always delete all data on the drive?
You should be able to reinstall and upgrade.
However a back-up of the data is a MUST.
Any change in the hardware or software of a computer may lead to some amount of data loss.
Here I can suggest a couple of links that can walk you through re-installing and upgrading Windows:
http://www.howtogeek.com/133254/beginner-geek-how-to-reinstall-windows-on-your-computer/ http://windows.microsoft.com/en-us/windows/installing-reinstalling-windows#1TC=windows-7
You should be able to reinstall and upgrade.
However a back-up of the data is a MUST.
Any change in the hardware or software of a computer may lead to some amount of data loss.
Here I can suggest a couple of links that can walk you through re-installing and upgrading Windows:
http://www.howtogeek.com/133254/beginner-geek-how-to-reinstall-windows-on-your-computer/ http://windows.microsoft.com/en-us/windows/installing-reinstalling-windows#1TC=windows-7
Thanks for the answers! One more question: my motherboard claims it is "8.1 ready" should install win 7 anyway or use 8?
It's up to your own preferences, I guess.
I personally use both Win 7 and 8, but I'm definitely more satisfied with Windows 7 despite all the 'perks' of Windows 8.