speeding fan on start up?

lenovo sff
on pressing start -the front fan revs to very high speed -and will not start
can anyone name problem?
SCARED, July 2016


done
thanks both
tried taking out -and putting back in the ram -as per google search -seemed to work
was a bit scared of doing stuff with the bios
thanks heaps

HAPPY, July 2016
A faster way:
Disconnect and remove the CMOS battery.
Press the start button.
This will discharge the remaining power from the capacitors in about 1 second.
Put back the battery and plug it in again.
Start normally to reconfigure the BIOS.

Be sure that any drive are correctly detected and that the boot sequence is properly set.
Also, if you have more than a single drive, make sure that they are in the correct sequence, with the OS drive been the first.
Last month, I discovered that the internal drives order can be arbitrarily changed in the BIOS.

Electro, July 2016
You already named the problem : Fan runs at full speed all the time and the computer won't boot.

You could try unplugging the box, popping out the CMOS battery and waiting 1 minute until the power completely discharged. Plug the PC back in, then put the CMOS battery back in and configure the system time in the BIOS and then exit and let it reboot. If it starts it should scan for a bootable device, find the disk and boot into Windows.

There's a few people have had trouble with 100% fan speed in Lenovo PCs. A simple Google search should give you lots of relevant threads - Hang on; you DID try a Google search for yourself, before posting here. You did, didn't you?

Anon, July 2016
link Click here to see other fixes for Lenovo.