Something Wrong With Team Fortress 2?

I just got TF2 free on Steam, and I find it very hard to move around. It seems like the controls are jacked up. For example sometimes I can't even move when using the w,a,s,d and when I can move, if I press one of those buttons, my character moves in that direction for the whole game even when I don't press anything and try not to move. I tried to changed the default settings to the arrow keys to move, and that only sometimes works. Also when I try to change my controls back, when I type in w for example to move forward, instead of w it puts in a number from 0-9, and same goes with any other letter I try and put in.