Lenovo PC won't boot

Hello!

I have a PC that won't boot.
It's a Lenovo 6234A1U desktop.
Yesterday it powered down by itself - then wouldn't turn on at all.
Today it will turn on - lights come on - but nothing is ever displayed on the monitor.
The CPU fan is much noisier than usual...
I tried another monitor - no difference.
I tested the PSU - it shows that it's fine.

My next thought is that the system board needs to be replaced - but that doesn't explain the noisy fan ... does it??

Thanks in advance for any help

Amber

 

Try taking out all the RAM and see if it will beep when you try to boot.

 

I pulled out both sticks of RAM, turned it on - same result.
No beeps - loud fan - no display ever shows up.

Amber

 

I guess you could put the RAM back in and with it unplugged take out the CMOS battery (small coin shaped watch-type battery) for a few minutes. Replace the battery and plug in and see if you get anything on the screen.

One other thing is make sure you have no USB devices attached when trying to boot but do have a keyboard attached.

If you still get nothing then it may be the board.