WinZip Pop-up Ads were very annoying and were NOT stopped by disabling WinZip notifier in Windows Task Manager. I contacted WinZip support and they were very reluctant to help with this but finally gave the following instructions:
Please remove/delete the 3 WinZip Update Notifier tasks from the Windows Task Scheduler to insure it will not be run.
Also Please delete the WZUpdateNotifier.exe file from the "C:\Program Files\WinZip" folder without causing any harm to the program.
After doing this, you will not not get any Promotional POPUP from WinZip application.
This worked for me and did not affect program use!