I and several of my friends recently have had issues with AVG. Its passing up bugs, and causes giltches galore. Once removed, her system went back to normal, but reinstalled, it glitched away. She has a paid version of AVG as well. Kaspersky isnt free anymore, oh how I wish it was. Nortons in my opinion IS a virus! Avast is free, but can be confusing. Avira isnt bad. Most internet providers give you at least some basic protections.

I LOVE Malwarebytes.com. its not anti virus, but malware, and pulled a ton of crud off my machine.

I hope yours feels better soon.