Removal of Anti-Virus Program

I have a two-part question. First, I have Webroot as my Anti-Virus program, however, I just found out that because I have Windows 8 that I do not need an additional AV program because I have Windows Defender, is that true? Ever since I installed Webroot, every page and site I click onto I have to hit reload/refresh 2,3 sometimes 4 times. I have tried everything to fix this too. I have cleared my cache, cache, history, I have even changed my encoding to Western ISO-8859-1, I tried Unicode too, but nothing has helped. It happens when I use Google Chrome, but wasn't happening on IE, but it's happening on there now sometimes too. So, my second question, would my firewall settings in Webroot cause this? And my other question above was, is it true that I do not need an Anti-Virus program because I have Windows 8 and Windows defender covers all of that? Thank you for any help that you can provide.

Respectfully,
BanjoWyatt:confused: