I assume this started happening recently and is a new problem and as that is (probably) the case, do you know which add-on it is? Or have you added-on a few new ones that you suspect are causing the trouble?
If that's the case, you can try disabling them through the add-ons manager. I'm using Vista, but hopefully you can get to (or have!) the same place*:
Control Panel > Internet Options (or Properties) > Programs tab at the top - Choose the "manage add-ons" button.
There are a few categories for the add-ons on the left. Find the one you want to disable,
left-click it once and press either "remove as default" or "disable" at the bottom.
I don't know if there are a lot of important add-ons, but don't go disablin' anything and everything. If you know for sure what it is or could be, turn that off. If you don't know... Well, I guess you can always uninstall and re-install. Or better yet, download FireFox.
* If you can't find it my way, I think you can go to your new "no add-ons" shortcut and go to Tools at the top right, then Manage Add-Ons. Should open the same window you need.
Note that I could be completely wrong here.
EDIT: No no no! I meant left-click the add-on you want to select. I always say right-click for everything.