My laptop running so noisily
Turned laptop on and the noise of the fan is making a noise like a car over revving. It has done this before quite a few times but it can be fixed by shutting down a nd restarting. But today no amount of shutting down and restarting is making the laptop run with its normal quietness.
It is not yet affecting ths software, apart from it is running a bit slower than usual.
Any suggestions what to do.