Hi! Sorry to hear you're having trouble.
Can you give some more detail on what's happening? Are you seeing an error? Does the game start at all? Does it crash, or does it freeze up? Can you also tell me which downloads you have tried?
It'd be good to check whether the game has created a log (there are instructions on where to find it in the "Log, save, and config file locations" section here on the store page). If it has, could you email that to the address under the Technical Help section of the store page?