I have an Acer laptop computer running Windows 7 Home Premium 64-bit. I use Microsoft Security Essentials as my anti-virus and anti-malware programs (I believe that Windows Defender is part of MSE). Last night I opened the Action Center and under the Security section, looked at the status of MSE and Windows Defender. The status window showed me that MSE was "On" but Windows Defender was "Off". I selected it and then clicked the button to turn it on, but the status remained "Off". I closed the Action Center and a short time later an information window popped up telling me that Windows Defender had stopped working. I was informed that I could restart it by rebooting, which I did. After the reboot, I looked in the Action Center again and saw that it was still in the "Off" state.
I decided that the program might have gotten corrupted somehow, so I decided to uninstall MSE and then download it again and reinstall. I did this and everything went fine. However, the Action Center still told me that Windows Defender was "Off" and I still couldn't turn it on.
The only reason that I could think of for this is that there is some other anti-malware program running. About a year ago, I purchase Malwarebytes and installed it on my main desktop computer, and I thought that I had also installed it on the laptop as well, but if I go into Programs and Features, there is no evidence of it. Is it possible that I did a Malwarebytes installation and it somehow failed to install, but managed to make some changes to the OS such that Defender believes that there is another anti-malware program running? Where should I begin looking to investigate this?
Thanks in advance.
Edited by hamluis, 18 November 2015 - 11:28 AM.
Moved from Win 7 to AV/AM Software - Hamluis.