1. Right Click on My Computer and Select Properties.
2. Wait a second for windows activation details to get populated.
3. Click on Change Product key link after your Windows 7 activation details are populated.
4. Enter New Product Key and click on next to activate your windows 7
done
ORRRRRRRR
Command Prompt
1. Click on start and type command (cmd) with run as administrator option or open elevated command prompt Click on Windows 7 Start Button Go to All Programs-> Accessories Now right on Command Prompt and select “Run as Administrator” from context menu. This should bring elevated command prompt mode with full Administrators rights
2. Now type following command
“slmgr.vbs -ipk <insert your new product key here>”
3. To activate windows after changing the key, run “slmgr.vbs -ato”