Many problems with internet explorer

Hello,
I have recently started having problems with internet explorer 7. I cannot download anything, no videos online will load, and windows contantly goes to (not responding). I have performed a scan using Semantic Endpoint Protection, which came back with nothing. I have also tried to reset the advanced settings under internet options and deleted all add ons. I cannot remember downloading or making any changes to the computer recently before this happened. Also I have my pop up blocker on, but still get a pop-up about every five minutes. Im using an Acer computer with Vista home on it. Any suggestions. Thank you.