Use the Manage Add-ons tool to determine which add-on is causing the
problem:

1- 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. Go to 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.

Ask the add-on's technical support for a version that is compatible with
IE 7, if any.

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Leonard Grey
Errare humanum est