There's bit of reverse engineering ;)
Follow These Steps:
1. Get a Resource Editor. [Recommended -- Resource hacker 3.4.0.]
2. Open the Executable in it.
3. You can see the resources in the .exe there. In the Left Pane Choose Icons-> Icon No->Right Click-> Replace.
4. Browse any other Executable or icon file.
5. Repeat Steps 3 & 4 for all other icons remaining.
6. Save .exe & Enjoy!
Note: Keep a backup of previous icon in case u feel like getting the previous look.
