game keeps minimizing itself need help!

It could probably be something which has nothing to do with the game at all. When you land on the desktop all over sudden but the game runs fine it's an indication some other software demands focus and pulls you out. This could be anything.
So please make sure you have no other programs running. Close your internet browser, your email software, twitter client, cloud sync software (i.e. DropBox), Skype, ICQ and so on.