It would help to know which version of Windows and which version of Internet Explorer. And the Exact wording of the error message. You can frequently search exact error message wording and instantly find a fix. If XP you might go into 'Computer Management' and look at the 'Event Viewer' error logs. Sometimes that will show the error and supply a link to a suggested fix. If you don't know how to access 'Computer Management' Click help off the Start Menu. Before doing too much perhaps try going to Control Panel and Internet Options - Clear IE cache & offline files as well as clear the History too. If you have a spyware program, you might want to run it also. One thing that can cause that IE must close message is a firewall... have you added a new firewall ? You can only have one firewall running at a time.

I wouldn't bother fixing Internet Explorer 7. I would up date to version 9. It's the most current version for the operating system Vista. Here is a link that might be useful: explorer/ie-9

No that article did not apply. Mine shows "Mod Name urlmon.dll". Zep, can I safely remove IE8 and the update via Control Panel? If so, will it automatically roll back to IE7, or how do I go back?

It has a link there after you highlight the event that takes you to a microsoft support page for the error details -- which may or may not have a known solution. Plus sometimes if you look on the Details tab for the event, you might get a hint of what program might be conflicting or some other piece of info that aims you in the general direction of what might be wrong. Sounds like maybe its one of the popular conflicts with a plug-in. Fairly easy to run from the start menu 'system tools/InternetExplorer(no plug-ins) Which means if that works all the time,,, you can go to Internet Options/ 'Manage add ons' .... and disable all of them,,,,, then turn them back on one at a time until you discover which one is the bad guy.