You know how you used to go to Windows Update with Firefox and get this:

Well If you install 'IE Tab' from the Startfox Addons Menu in Startfox 6 and higher, you will see something like this screenshot of Windows Update 'requiring IE'

  Notice the title bar: Microsoft Update - Mozilla Firefox

Sure, what kind of all-important system-required program disabler patch comes without a way to disable it?

Well, not this one!

Ya, so you disabled IE directly, what stops it in the background?

mshta.exe is a file that was probably on your copmuter since the day you first purchased it. Verify the disk location shown below to make sure it is not spyware or virus related. It's critical to check the folder as often virus writers use similiar names or place the same names in other folders in an attempt to fool you into thinking it is a good file. This mshta.exe file is a critical Windows file, it is used to open hta file types. This file is safe and it is not considered an adware or spyware related program. It will appear in your startup list.

(quote:  http://www.justtext.com/processes-tasks/mshta-exe.html )

However according to Symantec, there is a virus that likes to hide in it ( http://www.symantec.com/security_response/writeup.jsp?docid=2001-032318-5403-99 )

VBS.Elva.Worm

This worm uses Microsoft Outlook to spread. Using MAPI, it sends itself to all email addresses in your Microsoft Outlook address book.

Disabling of MSHTA.exe is also supported in Startfox from version 1.