I have a quick and silly question. Back in the day, I bought two keys for Windows 8 Pro for 30 bucks, but I think I lost one of them (and the emails, because I regularly wipe those). I've already upgraded my desktop to Windows 10 and wanted to upgrade my laptop today. I can't check whether this machine is using the same licence for Windows 8.1 Pro as my desktop did, however. So... Is that a problem? I could only find out that Windows 10 is linked to your hardware after upgrading from a 'genuine' Windows 7/8/8.1, but is there trouble ahead if I maybe upgrade twice from the same product key? That regular upgrade procedure tool can't seem to download the damn installation files, so I may have to switch to this install procedure. Just want to make sure it will work (if I use the same key by accident).