So we managed to figure this out over several tests over e-mail - the problem was something related to DEP (Data Execution Prevention) settings being mangled somehow on Eddie's home machine. One symptom of this was that the system dialog for controlling DEP options was all grayed out instead of having its regular options.

If DEP gets configured in some particular way it can prevent MoI from working - something like if ATL thunk emulation being disabled, as mentioned here:
http://msdn.microsoft.com/en-us/library/bb736299%28VS.85%29.aspx

Once we figured out it was related to DEP Eddie then figured out how to get things working - doing a
bcdedit.exe /set {current} nx AlwaysOn
and then a
bcdedit.exe /set {current} nx optin
followed by a system reboot got the system DEP settings unmangled and the system DEP options dialog working again, and MoI ran fine after that.

I just wanted to post this here in case anyone else runs into a similar problem with MoI not running on their system. If nothing happens when you try to launch MoI and system dialog for DEP settings is all grayed out you can try the above process.

Thanks Eddie for your help in debugging it and for figuring out the solution!

- Michael