How to decompile exe?

Question

reverse engineering

There is an application, the source codes are lost, I want to get them walking clumsy so that I can restore the project and edit it, some craftsmen found how to open it and translated it, but they don’t want to tell and give)
Here is the application itself It’s not mine, but from the Chinese, the browser mb virus swears, if you run it for everyone on a virtual machine, the password is on the archive 1
This is the value editor in the game, so I would like to make it acceptable for reading, the program language is most likely C
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