Toshiba Satellite P70 cooling fan

Thanks for your response Webworkings.
To be clear, I don't really have any problems other than the fact that the fan is going continuously and throwing out quite a lot of heat. I installed a piece of software called 'Speedfan' which reports the following temperatures:

HD0 = 37C (I assume this is the HDD)
Temp1 = 68C (No idea what this is)
GPU = 511C (No idea what this is)
GPU = 511C (No idea what this is)
Core0 = 59C (I assume these four relate to the CPU and vary slightly over time)
Core1 = 58C
Core2 = 70C
Core3 = 64C

I'm not sure whether these temperatures are considered normal or potentially damaging. I have read that, for some reason, components do run hotter under Windows 10. Some have accused Cortana as being responsible; others say that Service Host Local System is responsible and, having looked in Task Manager, of all the processes showing around 0% CPU 'Service Host: Local System (20)' stands out and indicates about 17%. I have no idea what this is, but it seems to be what is using the CPU at all times and for whatever purpose I don't understand, even though the only open programme is my Chrome browser.

I wrote a letter to Toshiba yesterday asking for their advice (that seems to be the only way I can contact them directly; the method they seem to think we should all use is some oriental-looking bird who invited you to ask a question and then really doesn't give any answers!), so I'll see if they manage to respond.

I could also telephone John Lewis technical support. They have been much more helpful than Toshiba in the past when I had a display problem that turned out to be down to using a third party AV programme (Avast) which Windows 10 didn't like! I rely on Windows Defender now.

Thanks, Webworking. I took your advice and, whilst still waiting for an response from Toshiba, telephoned John Lewis Technical Support. Their advice was to try three things:
1. Download and install a BIOS update.
2. Blow compressed air into the vents.
3. Back up all data and do a factory re-set. If this fails, they will take in the laptop for investigation and repair under warranty.

I have done (1), found two items and downloaded them both, then tried to install them. I received the following messages:
TC501756001 – "This BIOS is not for your notebook PC. Version of ROM file is same as that of BIOS"
TC50179300F – "Version of ROM file is same as that of BIOS"
So it seems that my BIOS is up to date.

I'll find a compressed air can tomorrow and try (2).

If no improvement, it will have to be (3), which will be a little inconvenient and time consuming but, I'm afraid, necessary.

Backing up is what I do regularly anyway. No, I'm not going to rush in to reinstalling, although the technician I spoke to at John Lewis suggested that was what I should do before sending it in for repair (if it comes to that), possibly to remove all my files, passwords, etc, for security reasons. I shall ask about that again before sending it in.
Is it better to send it in for investigation with the present set-up in order that they can see the problem as it exists? If so, I could remove all my files and passwords.

I took my laptop into John Lewis earlier this week and they sent it for repair (up to 28 days). No problems and very helpful, as always.
I'm afraid I can't say the same for Toshiba. I wrote a letter to them on 7 September, as I can find no way of contacting them directly online or by e-mail. I have still had no response. Perhaps they make good computers, but I'm afraid their customer support service is sadly lacking.
One learns by one's mistakes.

Of course I will. As it is still under the one-year manufacturer's guarantee, and certainly under John Lewis's two-year guarantee, I expect that it must be fixed or replaced.