I'm at the motor inn trying to save the girl ("Glenn's Damsel in Distress," as Carley put it) and I'm trying to get to her. I already got the screwdriver and everything and I'm at the part where you have to kill a walker with it. It's that first walker on the side of the RV; I whistle to get its attention, then hit it once, but when I try to hit it again, I can't, and get killed. At first, I thought it was just my mistake, but now I'm beginning to think the game's not responding when I click. Still, did this happen to anyone else and is there any easy way to fix it?