Over the last couple of days, my PC when starting up from cold displays CPU Fan Error - Please F1 to go to Setup.
Now, I will make it perfectly clear that my Desktop has not had a new Fan fitted since it was built in August 2014 and has never been touched!
Anyhow, after you going to BIOS setup and then exit; the PC boots up as normal. You can close it down and restart it again as normal without any error message. I have tested this when leaving the PC for one hour and then starting it up again. However, I left it over night and started it first thing in the morning. As soon as it booted up the error came up, again. The fan always kicks in when the PC starts, and the PC is useable.
I have ensured that there is no dust in or around the Desktop just in case things might be getting too hot, plus in the BIOS screen, I changed the setting for CPU from Standard to Full Power.

The BIOS is UEFI and when the in idle the CPU temp showed around 26 degrees when viewing from Operating System (in case Ubuntu using hardinfo).

The basic details of the machine are:
Intel Core i7.4790K CPU at 4GHz Asus Z97P Motherboard with 32GB of RAM.
So, I have two questions:

  1. Is this a problem with a faulty fan, and if so should I replace it? Or is it the motherboard with a bigger problem lurking around the corner?
  2. If it is not a problem - I do make the message go away? As I say it does not come every single time, only when the PC is left for a long while after use.