Windows 7: If I sell a used operating system on ebay will it still register....

on another PC?

Will whoever buys the OS off me have any problems installing the OS apart from having to activate over the phone?

If it is a Retail version, it'll activate without problems, as long as you don't have it activated on your machine, since retail version can be activated on any PC but just 1 PC at a time..

If it's an OEM or Upgrade, it won't activate. unless you call microsoft and explain that your motherboard died or something (although, it wouldn't be honest) and i'm not sure that they'll activate it.

Retail = Yes
OEM/Upgrade = i'd say, No.

I have a retail upgrade version of Win 7 Home Premium. I performed a clean install when I first got it with a new motherboard (and cpu, ram & HDD). I had to call to activate it over the phone. They gave me another key from what was packaged with the software. Since then I've done 4 clean installs on 2 different motherboards and not once have I had to call again. When I say 4 installs it's still only active on one computer!

Oh, and I was told by the very cute sounding CSR that it didn't activate the first time because there was something wrong with the key...hence the new key!