Can you decrypt .dat files?

Quote:

so im asking you simply if you can please decrypt .dat files.

The first problem is that a .dat file contain anything the programmer wants.
The second problem is that 'encrypt' is a generic word to say that data is unreadable by an encoding process.
There is literally thousands of methods of encryption, and for each method, each the encryption key gives a different encrypted result.
Giving a maximum of information about the .dat file, matters.
Because if .dat files is part of a game, the encryption method and key can be known already.

Without any information, you have more chances to win lotto grand price.

You can't decrypt anything without a fair amount of information:
1) Is it encrypted at all? Or is it just binary data you can't read? Or just zipped data without the zip header?
2) If it is encrypted, what algorithm does it use? Or which one(s) does it use?
3) What key? What initialization vector?

And decompilers won't help unless you decompile the EXE file and all it's referenced libraries and spend a lot of time working out what the code was doing (which without "proper" function names and comments since these aren't stored in executables is going to be really hard work) and where to find out what it stores where. You can't "decompile" a data files as they aren't compiled!

You can't answer any of that, and ".DAT" is such a common file type that the content could be absolutely anything.

Add to that that decompiling EXE files and fiddling with data files is normally a breach of terms and conditions and you are really on a loser here. Many game producers will kick you off the game permanently if you are caught cheating, and since your software skill level doesn't appear to be that high yet you are likely to stick out like a sore thumb if you try ...

I'd drop the whole idea if I was you!