Alright so my idea was some way to bind both 64-bit and 32-bit Windows executables into one application so if it doesn't run the 64-bit version it would then try the 32-bit one.
I was reading up about PE's and learned a little about MS-DOS Real Mode Stub and it says how it invokes an application (usually an error message). But every time I tried to do research about MS-DOS Real Mode Stub it seemed to only show error messages. So my idea was to overwrite the STUB with my 32-bit application.
My self being naive figured when the 32-bit operating system would run the the 64-bit executable it would fail and then run the stub file.
Is there any way to make my executable 32-bit/64-bit independent?
You could not create a single executable file, containing both x86 and x64 code. However you could create separate 32bit and 64bit applications, pack x64 app into the x86 app resources. On the program start you could check, that you are running x64 environment using IsWow64Process then if needed, unpack your x64 version and run it instead