I have a lot of "unregistered" program folders. Any way to find them all?

[octopod]

Basically, on my storage drive, there's a lot of leftover programs in my Program Files folder that were left over from the Windows 7 days. Since they don't exist in the program list as far as Windows 8.1 is concerned, is there a way to find them all so I could delete them?

The last thing I want to do is to have to look through every folder to see if it's actually installed or just there. There's [I]a lot[/I] of program folders.