Windows Defender & Avira report they are turned off; Can't turn them on. Is this a virus?

Okay so, came back from school, turned on the monitor of my family's desktop but there was no picture, so I rebooted the comp. First two times, it booted up into Windows but it hung. I shut my desktop off for awhile first before trying again, and the 3rd time it booted up successfully.

However awhile later, I noticed that there was this cross on my taskbar, telling me that both Windows Defender and Avira had been turned off. I also noticed that my audio service wasn't running for some reason. However I checked, and Avira was indeed running. Yet the Windows Notification thingy kept insisiting that they were both off. I tried to turn both of them on through the notification thing, but it just kept saying it was turned off.

So anyway...I started a full Avira system scan. It's still running now as I'm typing this. From what I described, was I probably affected by a virus? Or am I just being paranoid?

 

Usually I wouldn't be too worried immediately, if the Microsoft Security Centre gives an error.
New versions of security software are often not 'recognized' by the security centre.
However, in your case with a hanging computer and a program not responding, it sounds more suspicious.
Has anybody changed or updated security software programs in your absence?
Has the Avira scan found anything?

Besides running a scan with Malwarebytes'Antimalware, I'd also flush the current information, used by the Security Centre as described in this post (not sure what OS you're using).

 

If you're running a scan of your system, do it from Safe Mode just in case.
As for the hanging of your comp bit ... you will definitely have to check as Basek said and see if someone from the family changed something.

Running a stability test of your hdd would be good tood.