I have some old Python programs that I compiled with a tool called py2exe. Now I no longer have the sources but I would like to change the program icons to something meaningful. I'd also like to change the icons on some other programs to better suit my desktop. Is there a simple way to do this?
You can use Resource Hacker:
Although this is fine for your programs, it is likely against the EULA for the commercial applications you have so you may want to read over them.