WIN7 activation has been sent to your mailbox.

No need to install, just open it and click activate.

If the prompt "100M system needs to set the drive letter before it can reserve the partition", the solution is as follows:

Right-click Computer-Management-Disk Management. When you see a partition of 100MB, right-click it, click "Change drive letter" ... (c) ",give him a number, such as z, and confirm.

Then start WIN7 activation again.