Most of the time the problem is that wrong Product Key characters are being inputted. Try again and stress accuracy.
After three days it will enter Reduced Functionality Mode
which is the same for Windows 7 as Vista. The link explains how to extend activation until you can resolve the issue.
If your Recovery Partition will not run from boot then to continue taking advantage of the OEM Windows 7 license which you own for the life of the machine contact your OEM and order Recovery Disks which auto-activate during install.
Then you can come close to a clean install by following these steps to Clean Up Factory Bloatware.
There is also a way to back up the OEM-SLP factory activation in the factory install to use for Clean Reinstall, but it is not supported by these forums.