If you have more than one core you can always check if all of them are active for a specific program. Open the task manager, go to the application tab and look for the maplestory installer or whatever it's called, then right click and click on go to process. Once you're in the processes tab, right click that process and click on set affinity... Make sure all of them are checked, if they are... then I don't know what to do. :/