Laptop problem. I've had my laptop for many monthss now (4months roughly) but it has over the last

Question

I've had my laptop for many monthss now (4months roughly) but it has over the last month slowed right down and the voloume keys on my user name do not work and the volume symble has a ! on it and says there is a problem but this isnt a problem on the other user name. Also it is runing very slowly.