Common problem while creating installers is bad image which Windows displays for your program in Control Panel:
If you are using Inno Setup for creating installer this problem can be solved by adding one line to [Setup] section:
Usually this is enough but if your exe contains multiple icons you can select which one you would like to use. See Inno Setup documentation for details.
If you skip this line, Windows will choose the icon itself and usually it will be ugly icon which you can see on the screenshot.