1) Option 1 - put in a new hard drive and install Mint.
2) Option 2 - put in a new hard drive, find someone that has install DVDs for 7, and then try your activation code from the sticker on your computer.
Hard drives are big and cheap these days. Or pull one out of an older computer and wipe it and re-use.
I searched “install Mint” and watched a video. Didn’t need the entire 12 minutes to grasp that installing Linux is several Dantean heaven levels above my capabilities.
But thank you for suggesting it anyway :)