Are you aware we have malware removal experts right here on the forums? Best part is it's free!
If you are concerned that avast failed to detect some sort of malware, then you are in for a
rude awakening...there is no such thing as 100% detection. Each and every antivirus misses something.
As far as avast is to blame, what about software conflicts which could result in an infection?
There are too many variables to blame avast as being the culprit. Like Pondus said, "no way it was coming from avast."
edit: Please use respectful language in the future. Also you didn't ask about a refund in your original post.
I have been having a problem with something related to Avast infecting my search engine.
I get a msg "add ons slowing down your computer and then my internet browser changes to search tab bars coming up multple times