Uninstalling/Installing - good way to do it?

I'm trying to fix a problem I have with the game - in my latest save every match (pre-season and in-season) everyone on the pitch plays in a white kit. Rather frustrating. It could very well be down to something I've installed (although the latest kits are for the menus, not matches as far as I'm aware).

Therefore I'll try a reinstall/default game to see if it makes ANY difference. After which I'll shout at SI again

Is there a good way to go about uninstalling? Do I need to delete one of the 'seats' I've used? (PC). Input the code again? (After the nightmare first time around I'm slightly worried about this!).