DNS server error

[REDACTED]

I recently installed Avast and suddenly started having DNS problems (DNS server error) that have thus far only been solved by restarting the computer.
In researching the problem I saw that many people easily solved the problem by uninstalling a particular brand of antivirus software (not Avast).  I wonder if anyone else has had similar problems with Avast.  If so, is there a simple fix or should i go ahead and uninstall Avast to see if that fixes it?
Running Windows 8 on a HP laptop.

[Pondus]

I recently installed Avast

what AV did you use before avast?
did you uninstall it before installing avast?
did you use that vendors removal tool to clear all leftover files?

removal tools   http://singularlabs.com/uninstallers/security-software/

[REDACTED]

Thanks.  Apparently it was that simple.  The old antivirus had not been properly removed.  It has been a couple weeks now and all seems well!!