One thing you should do is update to IE11 as IE8 is obsolete. That might solve the problem. I don't use IE either but for security reasons I have the latest version.
Internet Explorer isn't obsolete, Windows 7 includes Internet Explorer 8 as part of the operating system. IE 8 will no longer be supported after January 12 2016. At that time Microsoft will make all but the latest version of IE obsolete and no longer support these.
Having said that, it is out of date to the point that it has the potential of being a security issue. Windows 7 will run better and have less error if you were to upgrade to IE 11.
Since you are not using IE as your default browser this should not affect how to get online. This may resolve the slowness issue you are currently experiencing.