How can i set up icon for my existing program.exe and icon.ico ( in the same folder ) using some sort of hidden (settings) file ?
Edit: i am aware of py2exe CustomIcon option, also about WinRar Sfx ...
Question is: it is possible in this specific way i described ?
do it like this:
If you dont have winrar then install it!
Then right click on your program.exe and select "Add to archive...", under "Archiving options" select "Create SFX Archive". Now go to tab "Advanced" and click on "SFX Options" on "General tab" setup all you need and add "Run after extraction" (yourprogram.exe) under "Modes" tab select "Hide All" under silent groupbox, go to "Update" tab and select "Update Mode" (Extract and replace files) and "Overwrite mode" (Overwrite all files) now go to "TextAndIcon" tab and put to title yourprogram.exe name and under "Load SFX icon from the file" add an icon you want! Click OK, and click OK again. Now wait to compile and you have your program with icon! 
Just have to watch where you want it to be installed, or if it doesnt have any install direction then you use "Unpack to temporary folder" under the "Modes" tab in "SFX Options"!
Think this will help you! :)
How to set up icon for a program?