IE7 has known issues.Spyware and such can cause such problems,have you run any scans?
Try running your AV and AVG ANTI SPYWARE
For the last week or so I have been experiencing problems with IE7.
I'm not sure if it is the browser that is causing these problems, but it works fine for a few minutes, but then it just seems to stop working and won't load any pages, but if I restart the browser then it works for a few minutes again and the same thing happens. I have reset IE and I still have the same problem.
I have noticed the same with Firefox. At the moment I am using Safari, and have had no problems like this. At first I thought it could have been caused by my ISP, so I ended up changing my Broadband plan and now I am wishing I didn't as it did nothing for me and I downgraded from a plan that is no longer offered.
If anyone knows what could be causing these problems, please let me know.