IE scripts are failing or Objects are not recognized in IE.

Scripts are failing when IE is upgraded.
User has scripts developed in IE 6 and they worked fine.
But user updated his IE to IE7, then the scripts which worked earlier are failing now in IE 7.

Reasons could be:
BHOManager add-in could be disabled in IE7.
This add-in is needed for QTP to interact with IE.
Enable this Add-in by:
Open IE -> Tools Menu -> Manage Add-ons -> Enable or Disable add-ons -> Select BHOManager Class
Check whether the add-on is enabled or not. It should be enabled.

Objects are properly recognized in IE 7, but not recognized in IE 8.
Reason could be: Protected mode in IE 8.
Check the above solution, then follow to disable the protected mode in IE.
Open IE -> Tools Menu -> Internet Options -> Security Tab -> Uncheck "Enable Protected Mode" check box.