Adware

Have an adware on my Mac from Pirate Bay.....keeps reminding me to renew my McAfee (do not have) and need to have Flash Player for this site and unpaid subscription reminder.....annoying.  Cannot detect the source....watched my Activity Monitor but could not detect any unusual activity.....even asked Google for the meanings of all the strange name listings (xxxxd, etc.) and none seem unusual.  Have run full scan from my Norton (the cheap 1 device one) and did not detect.....was sent an inquiry about my satisfaction with Norton and I remarked about this adware thing, but so far no response back.  Any help?  Oh, also tried a solution from one of the Mac magazines by downloading Mac Malware free version and doing a large number of steps, but still no luck....!  Boo hoo.....!