Windows 7 key not valid?

Where did you buy this copy?
Was the key printed on a COA and packaged with the disc?

i bought it at a memory express, along with the rest of my system. i dont know what you meen by coa

COA = Certificate Of Authenticity

It's the label that has the 25 character key printed on it. The keys are specific to their particular type. For example, a retail key will not work to activate an OEM version, and vice-versa.

check your zeros and Ohs, ones and Ls and any other possible typos

Hi  

Did it come in a box ? and if so what colour ?

All the best Brett