Try going to
https://www.mswos.com/ to see you order. But you need the order # to get in :(
This is why they said to save and print the email and keep it in a safe place when it came in.
As for exceeding the number of activations, just give the phone number a call like darkest.white said. I have a W7 key that I've used many times on my personal upgrades that I have moved to many different personal systems that I ALWAYS have to call to get activated. It's no big deal. Just be forewarned, that just by chance, that key is in use on another system, that system will be deactivated.
Now if you can't find your key email, but the key is in use on a working system, you can extract it with a program called jellybean (bing it).