Hello Anna, and welcome to Seven Forums.
It could be a bad installed add-on on IE8 causing the issue. You could check by running the Internet Explorer (No Add-ons)
in the Start Menu, All Programs, Accessories, System Tools. If it runs fine, then it's likely an a bad add-on. In your normal IE, disabe your add-ons
and enable one by one testing after each time to see if you find the culprit causing this issue.
However, I would also recommend to update to IE9 as well through Windows Update.
If the above doesn't help, then you might see if resetting Internet Explorer
Hope this helps,