This sounds like the infamous "IE UserAgent String Length Issue" at work again as of late. This is happening more and more due to really bad practices by MS...
Essentially, IE is sending a UserAgent string that is too long - usually somewhere over 200 characters. This causes the firewall of some sites to reject the connection request, and your browser to "error out".
You can check the content/length of your browser UserAgent string here:
http://www.enhanceie.com/ua.aspx
You might see something like this:
User-Agent: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 5.1; Trident/4.0;
.NET CLR 1.0.3705; .NET CLR 1.1.4322; .NET CLR 2.0.50727; .NET CLR
3.0.04506.30; .NET CLR 3.0.04506.648; .NET CLR 3.5.21022; .NET CLR
3.0.4506.2152; .NET CLR 3.5.30729)
You'll probably also see a big yellow warning box about your string being too long - this is what is causing the issue. You'll probably also notice the ridiculously long string content itself - full of seemingly every .NET framework version/update, as well as perhaps some MS Office related module versions/updates - THESE appended entries from MS are what are causing the problem, and need to be removed/deleted.
Apparently, MS decided to append IE's UA string with this nonsense every time you installed/updated a .NET Framework package, or certain MS Office updates/packages etc, thus creating the increasingly common problem over time. Essentially, the older a Windows install is, the more likely its going to have been updated with these packages, and the more likely the UA string will get too long.
Why did Microsoft decide to append the UA string with all this nonsense to begin with? Good question, and a very bad practice best left to MS to explain. Feel free to contact them about the issue.
Regardless, you can edit the registry and solve your problem. Go to the following key:
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings\5.0\User Agent\Platform]
..and delete everything aside from "Default". That should take care of the issue.
Good luck