Can't start avast! firewall in Windows 10

[REDACTED]

Upgraded to Windows 10 from 8.1 Pro x64, now I got notification Firewall is turned off.
Click Turn on and Avast Information says "Unable to start Firewall".

That's on a Laptop where Windows 10 is "Activated".
For comparison, on a Desktop machine (same make, same platform) where 10 is "Not Activated" (for who knows what reason) avast! Firewall is working.

[Asyn]

Repair Avast:
1. Control Panel -> Add/Remove programs -> Avast
2. Click on 'Repair'.
3. Follow instructions.
4. Reboot.

[REDACTED]

Thanks Asyn.

Tho, it is now called "Programs and Features" not Add/Remove programs. Has been since 8.1, at least.
Accessible via Control Panel, as you rightly say, or Right-click on Start shows it on menu. Windows key+x produces the menu too.

It happens the problem went away by itself, I notice today.

And, I'm wary of the Programs and Features now. It goes ahead and uninstalls items as soon as you click on them without asking for confirmation usually. The Repair option does display with avast! uninstall I'm glad to say.

[Asyn]

You're welcome.