I'm running Win 7 ultimate 64bit and I was using BitDefender 2017 (free version) and it was woking fine until a few days ago. I got a an Action Center notification that my antivirus was turned off, so I tried turning it on from there, but nothing happened, so I clicked on the icon to open Bitdefender and the little "thinking" circle appears next to the pointer, then disappears and then nothing. No error message, no open program, just nada. I even checked for the process in task manager, but its not under the processes tab or applications. There is however 2 tasks on the applications tab that just say "client" and "running" but if I right click on either one and select 'go to process' again, nothing happens. So, I got rid of Bitdefender to try a different antivirus, but now none of them will install. I've tried AVG, Vipre, and Avast. Im able to download the installer, but when I click on "run"... NOTHING HAPPENS! I'm also unable to turn on Windows Defender and when I try to open System Restore (I'm starting to feel like a broken record) nothing happens. Can someone Please help?
You would be surprised how many people don't try that first. It is up there with the trying to mess with the battery because your computer is turning on but the display isn't. You could try running one of the internet based antivirus programs. I know there are a few, to see if it can find any problems that might be the cause. Also, have you tried going back to a prior point (earlier system restore point) before the problem started?