Right click on your IE7 desktop icon, select "properties" from the drop down menu, click on "programs" tab and at the bottom you should see a button marked "manage add-ons".
Click on that button and it will bring up a list of add-ons to your IE7 browser, in that list there is a heading called "pulisher". In that column you will see a list of currently installed add-ons, who they are from and whether they are "verified" or not, if they're not they "could" be causing instability issues so click on one at a time and disable it until you find the one that is prolly causing your problem!
Hope that was clear enough, I'm not good at explaining sometimes!
Let me know if you need more assistance Rose!

Injustice will be avenged.
Cofiwch Dryweryn.