Re: convert exe to different extension
...and on top of what root's said, and just to clarify, you can't just change an exe to a bat file. A bat(ch) file is just that, a batch script of tasks to run that you can open in a text editor. An exe(cutable) is a compiled binary that you can only change in a hex editor.
If you want to view the original source code of the exe, you need to find it somewhere (it won't be in the exe) and then open it, then recompile it if you want to change the contents. In short, if you're asking, the answer is to all practical purposes a straight no!
Save the whales, feed the hungry, free the mallocs.