Hahahaha this is what you're up to
I'm not sure what is causing the problem but after the v.95 Maplestory patch to add mechanics into the game, a lot of players have been getting the "Maplestory.exe" has stopped working error. I think its only been effecting Win 7 and Vista users. Anyways heres a tutorial on how to fix it.
Step One:
Open up your Maplestory folder, right click on maplestory.exe and go to properties. Click on the Compatibility tab and untick "Run this program in compatibility mode for.." when finished, click apply.
Step Two:
Do the same thing as Step one but with gamelauncher.exe, make sure you click apply when finished.
And you're done! , it should be fixed.
There is no guarantee that this fix will fix your problem as there are MANY other ways that could cause the same error. But if this error occurred after patching the v95 patch then this method should work.
Picture Tutorial,
Hahahaha this is what you're up to
im happy my maplestory is working fine but u can also just reinstall it
i sent a ticket to nexon and they helped me out