First of all thanks again for continuously hearing my problems. I didn't want to post but I've tried everything I can think of to resolve this issue...
The issue is I am unable to reach the log-in pages of any websites.
The common "this page cannot be displayed" window comes up. I am running windows explorer 8, and my flashplayer is up to date. My security, filtering, and pop-up blockers are low(and off in some cases) while trying to tackle this issue. I have wireless and I even temporarily took the signal of someone else to make sure it wasn't my internet provider...yet have encountered the same problem. I am fully able to log-in to websites on a friends computer, so I'm all out of ideas. This is something I've never experienced before.
The fact that it's only login screens makes it really seem like you have some type of malware on your computer. Did you have any recently that you thought you may have removed?
Try clearing cookies, cache and all that. Also try logging into sites using Chrome, Firefox, or IE9.
When you say you used your friends computer, was this on your wireless network? If not, try it on yours just to be sure.
If you can access the login pages using your friends computer on your internet, and still can't using Chrome, Firefox, or IE9 on your computer you most likely have a virus. It's very weird that it's only login pages.
EDIT: Just remembered, also trying doing it in Safe Mode on the various browsers.