Using win7... received email attachment from inside my company with .pdf.exe suffix. Unfortunately, I opened it. Now all .exe files go to acrobat where error message is displayed that ".exe file cannot be opened". Even 'task manager' and 'regedit' can't open.
Was able to uninstall acrobat (version X) and now laptop back to normal. Tried installing version XI, but same thing happened again.
It's more than likely that you're infected with some kind of virus or malware. Ask your IT people to run an anti-virus and anti-malware scan on your PC. Also, they should really block executables from being sent over email.