>>>I don't know if they install them identically. This is farily big organization and I can't say that they know themself.
>>>
>>>As far as registry, I am reluctant to hack into the registry on their computer. I may (or may not) make my application work but the liability is such that I may be responsible for any other problem they have with this PC (with some other application).
>>
>>
>>Keep a list of operations done as an undo list. :-)
>>
>>Actually, I don't recommend hacking into the registry. But it may be easy to see that a particular DLL is registered on one machine, and not on another, causing a silent failure.
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>>
>
>In this case I will need to know which DLLs to check for in the registry. Since I am there are tons of DLLs registered on a typical computer. Thank you.



Start with the DLL list. You can use Visual Studio and other tools to see which ones are loaded during program execution on the "good" computers.

Scan the registry and weed out all that are the same on both computers.

Computers don't do things magically. There is a solid reason why it's failing on the one computer. By identifying the differences between the two, you'll be able to track it down.