When you "clean install" are you downloading the release again from the website each time or are you always using the same executable you already downloaded ?
If not, try another clean install with a new download.
Is your computer a laptop with an Intel chipset and a graphic cards ?
If yes are you sure Construct 2 is not using the Intel HD chipset of your computer ?
I have downloaded one that day and have used it for all of them.
It is a laptop with intel hd graphics. I updated the driver, uninstalled C2 then reinstalled it with a new .exe from the site, but the icons are still bugged...
I have a dell xps 15 9550 (i5 6th gen and gtx960M) if that helps...