If its a wired controller to USB then should not flash as long as you dont press the big green X button with your drivers you installed.
If its a wireless controller, you need to purchase the adapter they sell for PC use.
I too have the game, what it is...is that you have unlocked it from the Car Dealership to claim it, not under your garage. I am only at level 18 so far, game is enjoyable, but difficult to drift.