so now i bought myself a new pc and i had a windows 7 retaill cd lying around and i installed it but then it asked for the key and ive used my key up already on another pc and i still wanted to install windows so ive entered the key and the install got finished. and after some time i wanted to instal new windows 7 and the oem is more cheap so the question is can i install windows 7 home premium oem over my current windows 7 (unactivated) ?? and i also had ubuntu 12.11 on my pc