.EXE files won't run

Hello,
I am running windows 7 on my dell and I began having difficulties with .exe files. None of the .exe files will run. I tried opening regedit to fix the issue, and I tried downloading malware removal tools, but once they download, they will not run.
Please help. - I have access to a second hp desktop, also running windows 7, but I need my laptop for work.

Thank in advance.