Microsoft Surface Pro Teardown
First extract your Windows product key using magic jelly bean. Then you need a copy of Windows 8 or 8.1 Pro. Your product key will work. Here's the tricky part. You need to make a Windows 8 Thumbdrive with GUID Partitions formatted as Fat32. (Do not use MBR partitions with NTFS). There's instructions on YouTube for that.
I used my thumbdrive to clear the recovery partition and do a clean install. Don't worry about drivers. Everything will work even before updates.