Under the browser - Press ALT (for the folder option menu) > Tools > Folder Options
Then the 'View' Tab and untick 'Hide extensions for known file types' if that is ticked.
(Microsoft's way of easily hiding double extension viruses from you, eg. game.exe.vbs will show as game.exe but will try run as a visual basic script - ensure this isn't the case)
If it isn't a double extension, then it's safe to move on...
Right-click the file and select 'Troubleshoot compatiblity', this will run it under compatiblity mode but try auto-pick one for you. If it works, run the game then follow the instructions to keep those settings. If not, cancel.
If it is a 16bit Application, you can not run it on a 64 bit OS. There is no way around this.
If the application is corrupted, it might not be detected as a valid Win32 Application and run as a EXE. You will need to re-download the application.