Bought a SurfShark annual only to find out they no longer allow installation on a Windows OpSys earlier than Win10. So if you have been holding out from 10 or 11 because of all the NSA backdoors or whatever, you unfortunately won’t be able to use SS.
FYI - their tech support was very helpful as far as was possible, and a refund was not a problem.
On an old pc like that the easiest way to place it behind a vpn is with a router. Install the vpn on the router then everything connected is protected.
edit…or install linux on the old pc, runs like new and a vpn will work
They better allow updates but even if they don’t it doesn’t matter that much as it works just fine on W7 as is. It’s on two systems with that. I really don’t like updating something unless it’s beneficial to me. If it ain’t broke, don’t fix it. They fix one bug and add 10 more. Been there, done that ** Got paid well for it too 
The only issue is most newly discovered vulnerabilities will not cause an update from MS, so hackers know you have W7 and try to exploit or wait for you to click something and boom. Some companies will replace machines instead of stay on W7 even though they never touch the public internet since it is considered unlikely, but a way inside a network during file transfers, patching etc.