I had this problem myself. This program was pretty sneaky. It never mentioned it was installing a program onto my computer, but I should have known better. No genuine theme for Windows 7 or 8 uses an exe file to load :-/ And for some reason this program doesn't show up in the programs list in the control panel. Pretty underhanded if you ask me, they obviously don't want you to be able to uninstall their software. Malwarebytes detected something in their software that it considers to be a PUP (Potentially Unwanted Program)as well.
So to delete this you have to do it the old fashioned way. Go to your C: drive and navigate to the Program Files (x86) folder. In that folder should be a folder named Expotheme(s). Delete it. If you are using Windows 8 you can delete the Start Menu app drawer tiles by going to the tiles in Metro, right clicking, choose "Open file location". That should get you to the folder with the shortcuts in it. Go up one level. Should be C:/ProgramData/Microsoft/Windows/Start Menu/Programs and delete the folder for Expothemes. The next time you start Windows it will not be in the app drawer anymore. Hope this helps :-)