CPU does not start

Since it seems to try to start up, what could very well be happening is that the cooling ducts or CPU heat sink could be clogged with dust and dirt, or the cooling fan itself it non-operational. Computer CPUs, if not given proper cooling, can overheat in a matter of a few seconds. Therefore, most will auto-shutdown to protect themselves. Check the inlet and outlet vents and the CPU heat sink for clogs. Also verify that the cooling fans run when the unit is energized.

Re : When i press the power button, the lights all light up, the cd rom drive spins for a second and that's it. No fan, No Post, Blank Screen. After a few seconds, it shuts off and then turns back on.

That is generic hardware fault, any faulty device can cause the problem.

The motherboard must be started with a minimal set of devices to troubleshoot.

Start motherboard with only CPU, power adapter connected (faulty battery can cause the problem), heathsink, display and one memory stick. Keep unplugged HD, optical units, keyboard, minipci cards etc.

If problem persists, eventually test the motherboard using a post card(PCI & ISA PC Diagnostic POST CARD MOTHERBOARD TEST CARD) to ensure that new motherboard is not faulty, and then if cpu has not been replaced with the motherboard, replace CPU.

check the fan

it seems that you have damage memory card replacing may fix a problem but its better for it that you bring it to a technician in order to check much better because the motehrboard may possible be the problem.

It should start for a few seconds, the fans should spin and then stop. You should be able to power it up as per normal. If that is no the case then you are having hardware issues which could be the Power supply

Try replacing the power supply - I had a similar problem that was fixed that way. If that doesn't work, it's probably the motherboard itself. The CPU is also possible - have you overclocked it or otherwise cooked it? Is the CPU cooler/fan blocked with fluff, or has the fan been slow (or stopped) - noisy fan is a sign of bearing stiffness/partial seizure which slows the fan and lets the CPU get too hot. If the CPU is fried, you get the symptoms you describe (MB won't start the PS)

May be there is a problem in the windows, but suppose it is not booting at all.

First Check once more your boot options from bios menu
Second If it still the same thing, extract your battery out of your laptop for 12 min, then try to power up your laptop pluging in your power cable(don't use your battery)
Third If it still not working, there must be a problem in your cooling fan, so check it, also check your motherboard & your graphics card (Most of this problems happens due to a problem in the computer cooling system in motherboard & graphics card)

Hope it works for you Christos

I guess it is a power supply failure can you try and plug it directly to light without using battery remove the battery before you power it on then notice how it behave then you will know the actual problem if it power on with light then it is battery problem. if not the check the harddisk maybe it is not properly fit in. or does it show bios setting or welcome bios

Does the power supply fan spin when you switch it on ??

Do you hear a"posting" beep??

Does the CPU fan start to spin??

If no to all of these probably dud mobo.