Re-installing Windows

So I would like to switch hard drives in my laptop but i have an oem version installed and I don't know the key so im not sure that i can re-install it.

My two questions are:

Can I re-install an oem copy of windows on a different hard drive?

and

How can I find my product key?

 

Your product key is usually on a sticker on the bottom of your laptop. If you can't find that or it got worn off somehow, you can find the key in your system properties.