When I switch on the PC it fan prongs(processor fan runs for few seconds). Then I remove the RAM, no error beeps. My board is INTEL D865GLC.
Someone say it it a faulty of Northbridge IC and filters problem in mainboard.
Do you have a system speaker installed so you can hear the beeps? Many motherboards and cases don't come with them anymore. That's a pretty old motherboard. Did it beep at boot when it was working correctly?
Here's a checklist that will help you narrow down what the problem could be: