Hi Jan. I'm Greg, 10 years awarded Windows MVP, specializing in Installation, Performance, Troubleshooting and Activation, here to help you.
Malwarebytes is the industry's undisputed best on-demand scanner, but unless you get regularly infected you don't really need it's real-time protection. But AVG is more of a problem.
No expert in Forums - where we see the most cases, by the thousands - recommends Avast, AVG. Norton or McAfee, but we solve many problems by uninstalling them.
I would uninstall any 3rd party antivirus in Settings > Apps > Apps & Features and try running only built-in Defender which gives adequate protection, best Windows performance, least issues, and is from Microsoft who knows how to protect their OS best.
After uninstalling run the cleanup tool for the AV here:
https://www.bitdefender.com/consumer/support/an...
Restart the PC, then type Security in Start Search, open Windows Defender and Firewall Settings, there and in Windows Defender Security Center fix anything that's flagged.
Next download, install and run a full scan with the best on-demand scanner Malwarebytes from https://www.malwarebytes.com/mwb-download/
In it's Settings > Protection > Scan Options enable Scan for Rootkits.
Then on Scan tab choose Threat Scan and Run Scan.
Clean up anything found, restart PC and then run again until it comes up clean.
Download, install and run a full scan with the AdwCleaner from http://www.bleepingcomputer.com/download/adwcle.... Clean up anything it finds and restart PC.
Next check for damaged System Files by running System File Checker from Step 10 in this checklist:
http://answers.microsoft.com/en-US/windows/wiki...
If this is not enough then move to Step 11 to do a Repair Install which saves your files, apps and settings while reinstalling Windows, solves most problems.
If you want to keep Malwarebytes as an on-demand scanner then you can disable its Real Time trial version in it's Settings > Accounts tab. You do not need to use MBAM Real Time unless you get regularly infected and Defender is not enough to protect you.
Feel free to ask back any questions. Based on the results you post back I may have other suggestions if necessary.
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