My activation key is invalid after reinstallation of windows 7

[Sacheen]

what to do for that problem accur

 

[smorizio]

try running windows updates and see if the error stops..sometime you have to run the windows validation tool. after all the updates are installed. if windows still errors out contact microsoft for a new key.

 

[Jason Light]

Call Microsoft. They can reactivate your product key so it can be reused. They have toll-free numbers in most countries as far as I know.

 

[tinmann]

Did you re-install on the same pc? Did you change hardware like a motherboard? If not there should be no problem. If it's oem software you can't transfer it and if you make major changes like a motherboard upgrade you get screwed too.