Internet Explorer will not stay open

I have a machine running win98 w/IE 6.0 and all the latest service/security packs and patches applied. When I try to open IE I get the message that IE has encountered an error and will shut down. There is a check box that is checked by default to restart IE so things just go in circles.
I have uninstalled, rolled back to previous versions (back to 5.0) and with very simular results.
I order to have a browser I am using Opera which is OK but I really want IE back.
Help!