Sometimes when you start internet explorer- 6 you found some error.
“Internet explorer has encountered a problem with an add-on and needs to close”
Because some add-ons files are destroy, crashed or not compatible and when you trying to open internet explorer its show this type error, but you can solve this problem, disabled following add-ons whose create error.
For disabled add-ons follow these steps
1.When you found this type error dialog box, click on advanced button.

2.Choose Add-ons currently loaded in internet explorer (2), select add-ons (3) in add-on encountered a problem area and then select Disable and click ok.

3.Click ok add-on status dialog box.

4.And restart internet explorer.

