Hi,
For this problem, firstly, please check if this system have installed any other security apps or firewall. Windows would turn off Windows Defender when installed any other security apps by default.
On the other hand, when you trying to enable Windows Defender, please be patient to waiting for if there is any error message pop up. If not, please check Event Viewer if it identify the problem.
You can also use following command to fix system components for test:
Open CMD with administrator account, type the command below and press Enter.
DISM /Online /Cleanup-Image /RestoreHealthLou979,
We have received some reports from other users that they received the Liam.X pop up when using a Windows Store app, specifically Magic Jigsaw Puzzles. Can you tell us if you are using the same app or if the pop-up occurs when you are using a Windows Store app.
Edit:
Also, how did they remove it? Did they install another Av on your device?
Also try sfc/ scannow in admin cmd
- Edited by aw00t 13 hours 30 minutes ago
Edit:
Also, how did they remove it? Did they install another Av on your device?
Also try sfc/ scannow in admin cmd
- Edited by aw00t Saturday, July 25, 2015 5:52 PM