How to find the UpgradeCode and ProductCode of an installed application in Windows 7

Question

I have an application installed on my machine. I also have its source code but somehow the ProductCode and UpgradeCode of this application were changed.

Now I want t

Answer 1

If you don't have the msi and you need the upgrade code, rather than the product code then the answer is here: How can I find the upgrade code for an installed application in C#?