Problem with EXE Files

Hey guys, this is my first post and I really do hope you can help me. This never use to happen but since a few weeks ago, all my .exe files have seemed to become infected but still happens to all .exe files which I download. They now have a new icon, which has the letters 'jpg' for some reason but also they wont open. If you double-click on them, all it makes them do it become 'hidden'.

This problem is really frustrating. Hope you guys can solve this for me.
Cheers

Ben