Something switched off Avast, not working after boot scan.

[REDACTED]

Hi,
After doing an avast boot scan I noticed the orange 'a' in the lower right corner was missing.
Then a flag appeared saying I have no anti-virus installed.
When I click the avast desktop icon the cursor spins for half a second then nothing else happens.
When i try to start the avast ui exe from the programs file, it does the same as above.
Action center said both avast and Defender were off (Defender, that comes with Windows 8 )

What could have switched off avast, and is stopping the ui from working?

Extra info:
I pulled the network cable out.
Ran malwarebytes - which was clean
Also switched on Defender and ran that, which was clean.
There are about 20 errors in the event log for shortly before the boot scan that say things like:
"The Service Control Manager tried to take a corrective action (Restart the service) after the unexpected termination of the Network Store Interface Service service, but this action failed with the following error: An instance of the service is already running."
or
"A corruption was discovered in the file system structure on volume ??"

Thanks.

[Eddy]

Check the taskmanager.
Is avast running there?
If so, it can be a well known bug in the security center.
If that is the case, just reset the security center.

If avast really is off, see if a repair solves it.

You also may want to follow these instructions:
https://forum.avast.com/index.php?topic=53253.0

[REDACTED]

Check the taskmanager.
Is avast running there?
If so, it can be a well known bug in the security center.
If that is the case, just reset the security center.

If avast really is off, see if a repair solves it.

You also may want to follow these instructions:
https://forum.avast.com/index.php?topic=53253.0

Thank you for the reply.

Avast is listed in the task manager but doesn't do anything, it is using 0% CPU, this doesn't change if i do something like start a program or open a browser page.
There is no tray icon for avast and AvastUI.exe does nothing.

I've only found information on resetting the Action Center status using the avast tray icon, is there another way to reset it without the tray icon?

Thanks.

[Eddy]

See if a repair of avast solves the problem.
If not follow the instructions in the link I gave you.