Windows 10
Windows 10
You're considering switching from Windows 8.1 to Windows 10 with your temporary key, and you're curious whether this will make the change permanent. Since you only have a temporary key, upgrading to Windows 10 might not lock it in unless you activate it properly afterward. If you don't want to risk losing access, it's best to use your existing Windows 7 key first and then upgrade to Windows 10 manually through the settings.
You should avoid playing games. I experienced frequent crashes with Steam every 20 minutes. For now, stick to Windows 8.1.
It doesn't matter which version you choose; both 7 and 8.x will be upgraded to Windows 10 at no cost.