I agree with what others have said here - leave Cool and Quiet on for a laptop. If you need extra power the CPU will throttle up. There's no reason to have it maxed all the time. C&Q will extend battery life. Further, frankly, many laptops can get on the hot side if you run them full blast all the time.
Also, I tend to doubt your grandmother has noticed any performance problems with the machine. Most people have a laptop for a reason, and will gladly trade a little annoyance (time for CPU to throttle up) for longer battery life any day.
If you insist on turning it off, try and set it up so it is only off when the laptop is on AC power, and on when on battery power. You should be able to do this in the power control panel (I think).