Pixel.adsafeprotected.com

I've been getting pc slowdowns lately and the occasional pop-up with an indication that Pixel.adsafeprotected.com is the culprit.  Since NAV never picked up on it, I tried a couple of other free anti-malware tools: Malwarebytes and Bitdefender.  After scanning, neither turned up that particular malware.  I ran Norton Power Eraser and it also failed to find it, but it did let me know that I had dplol.sys and that it needed to be removed stat.  I okayed that and restarted the pc, only to find out that the removal failed.

I did send a note to Symantec indicating all of this but it seemed like more of a survey follow-up than an actual request for help.  I don't have a lot of confidence that I'll hear back from anyone.

Can anyone give me advice on how to proceed?  Thanks.