I keep a squeaky clean Windows 7 PC and had the same pop-up and redirect from http://www.samsclub.com
only when Ad Block Plus was disabled. I disabled it for troubleshooting because something was not working properly on another site.
The pop-up opened the http://www.samsclub.com
in a new tab and redirected the current tab to pt21na.com with the same contest, investment, and pc repair crap.
The PC was scanned with Symantec Endpoint, Malwarebytes, Kaspersky Root Killer, and Emisoft. Nothing found. So I then ran Google's Chrome Cleaner and it found nothing. It then offered to reset all setting, clean cookies but keep bookmarks and saved passwords.
Now I get no popups from http://www.samsclub.com
with Ad Block Plus enabled or disabled. This makes me think it must have been something in the browser and I glad it is now gone.