At first, it is to take a backup (copy and paste in a secured place) of your imageres.dll (the location is C:\windows\system32\imageres.dll) , and also Take Ownership
Suppose we will change the games icon
Now open IcoFX. Go to "Tools" tab, and click on "Resource Editor" (as in pic1) . In the Resource editor window, click the Folder icon (as in pic2). It will open in system32 , just type "imageres.dll" in the file file name box and click "open" (as in pic3). So now all the windows system icon is open in front of us along-with the relevent resource number. Our games icon is #14 (as per pic4), which is to be replaced/hacked . So we may say bye - bye to IcoFX now.
Now open Resource hacker. Click on File > Open ( as in pic 5). It will automatically open in system32. You just put imageres.dll in the file name box and click open (as in pic 6). In pic 7, click on the "+" sign in front of "icon group". So icon group will expand as pic 8. Click on th e"+" sign in front of 14, it will show *1033; click on it. Notice now the game icon in the right side pane. Now right click on *1033 and click on "replace resources" (as in pic 9). in pic 10 window, click on "open file with new icon" and browse for it. when you browsed, pic 11 window will appear. Just "select new icon" and "replace".
Now again file > save as > imageres.dll (in desktop, to found it easily) as per pic 12. We have taken ownership of the original imageres.dll earlier, rename it to imageresOLD.dll, and paste the new imageres.dll created by us in that location. You may either restart windows or restart explorer using task manager now. After restart, see the game icon in startmenu as fimal