Anil said:
My computer is not booting by pressing power on button as it would normally.
When I press power on button the LED's of connected accessories lights up for
few seconds and nothing happens.
Thanks for your response.
That flash you see, especially of the LEDs on the keyboard, are the
result of the CPU sending out a Reset signal. That's needed to ensure
the host and devices are at a known base state.
Maybe the heatsink fell off the CPU. The BIOS sees an overtemp
condition and halts the computer. With the fan on the heatsink on the
CPU, the CPU will heat up very quickly.
Could be the CPU fan is broken and doesn't spin anymore, or the wrong
fan was installed (you didn't say your host used to work, just what it
is doing now). The BIOS monitors the RPM for the CPU fan. If the RPM
is too low or zero, the BIOS halts the host because it is being told
there is no cooling for the CPU.
Could be your PSU (power supply unit) went south. If it can no longer
handle the current load of your hardware when it is first powered on
then the power-on logic on the motherboard will shut off the PSU.
Do the intake/exhaust fans and the PSU fan even begin to spin when you
press the Power button? Do you even hear the hard disk whine as it
spins up?
Did you or anyone else recently open the computer case and putz around
inside?