When the problem occurs, are any errors being reported in the Windows Event Viewer? Usually when Forms causes Internet Explorer to crash on start up an entry is logged to the application section. Is there any entries for the date\time of when you tried to launch the Forms Application?
If there are and they mention a problem with jvm.dll my next step would be to disable all Internet Explorer third party extensions. One method to do this is to navigate to Internet Options (start --> control panel --> internet options) Once there, click the advanced tab and look for the following entry:
Enable third-party browser extensions*
De-select this option (un-tick it). Click Ok and exit Internet Options.
Ensure that you have closed all Internet Explorer windows and there is no Jinitator\Java console icon showing in the Windows task bar.
Retry your Forms application.