This may help:
Third-party add-ons for Internet Explorer, such as ActiveX controls and
browser toolbars, can cause problems if an add-on is damaged or if an
add-on conflicts with Internet Explorer 7. To determine whether the
error is caused by an add-on, run Internet Explorer 7 in 'No Add-Ons' mode:
Start > All Programs > Accessories > System Tools > Internet Explorer
(No Add-ons)
Test Internet Explorer to see if it works correctly. If the problem no
longer occurs, one (or more) add-ons is causing the problem. In this
case, use the Manage Add-ons tool to determine which add-on is causing
the problem:
1) Open Internet Explorer 7 > Tools > point to Manage Add-ons > click
Enable or Disable Add-ons.
2) In the Show box, select 'Add-ons that have been used by Internet
Explorer' to display all add-ons that are installed on the computer. For
each item in this list, select the add-on, and then click Disable under
Settings. When you have disabled all the items in this list, click OK.
3) Exit and then restart Internet Explorer 7 > Tools > point to Manage
Add-ons > click Enable or Disable Add-ons. Now enable a single add-on,
then exit and restart Internet Explorer 7 to see if it works properly.
Repeat until you determine which add-on causes the problem to occur.
After you have used this process to determine which add-on(s) causes the
problem, disable that add-on or uninstall the software that installed
the add-on. (You won't need to uninstall the software if it gives you
the option of not using a browser add-on.) In any case you should
contact the vendor that provided the add-on for a solution.