Having connectivity issues with my acer laptop...?

I just yesterday had comcast bring me an internet modem, and they installed their software, then for free I got McAfee, so I downloaded that. I also downloaded glary utilities. Ok so, My modem is working fine, I have a little world in the corner, but the internet explorer is very unstable, and keeps not responding. Is the problem with Mcafee or internet explorer? I have also ran the comcast desktop doctor for internet issues and it says everything is working fine.