I had a very similar experience once when doing a reformat. The label was unreadable when it came time to enter it. I thought about a few options. Eventually, I decided to call Microsoft. I didn't expect much, and I was completely truthful with the agent on the phone. She asked me a few questions; where did I buy it, how long ago, etc. In the end, she seemed satisfied with my answers and simply gave me a new Activation Code right over the phone. I was surprised, but very thankful. Call them if you can't figure it out. They may help you like they helped me.