can not start my system using power button

[arnuld_aqua]

I turn on the power-button of my cabinet and i don't even get the BIOS screen, monitor does not even turns on to show me soemthing. The disk-usage as shown by the red-light of cabinet is 100% bright red light like if it is continuously accessing the HDD.

Then I press the reset button (because the big power-button does not work at this time) and it shows me the BIOS screen. I cleaned up the dirt form the FAN and the heat-sync, I cleaned up the RAM slots, there was lots of dust on RAMs themselves. Now even after checking the power connection on the MOBO and the HDD cables (one IDE and one SATA) I still don't get the BIOS screen at first try. I always have to press the reset button after power-button to get my compuetr working.

Any ideas on the this strange issue ?

[rcgreen]

Try replacing the switch. My computer recently began
acting strangely, and the switch was the problem.
The power switch is a momentary contact switch.
It only conducts while held in. Mine would stay
stuck in after pressing, and the computer would
shut down after a couple of seconds.

[arnuld_aqua]

Try replacing the switch. My computer recently began
acting strangely, and the switch was the problem.
The power switch is a momentary contact switch.
It only conducts while held in. Mine would stay
stuck in after pressing, and the computer would
shut down after a couple of seconds.

well, I can't replace the switch, it comes and glued with the cabinet itself. I tink I need to buy a whole new cabinet

[arnuld_aqua]

Do you happen to have another (known to be good) power supply around that will be able to power that pc?
Give it a go, lately I've seen lots of problems caused by flaky power supplies (I've had a few problems myself).

Here is what I did in order:

• I changed all the BIOS seetings to default and then rebooted. Problem not resolved.
  
• Removed all HDDs and DVD-Drives and USB wires connecting to MOBO. Now MOBO has only 2 things: power supply and 2 RAMs in 2 slots. Then tested it but same problem.
  
• On the empty MOBO, I checked RAM and slots with different combinations of 1 RAM and 1 slot. Problem not resolved.
  
• On the empty MOBO, I removed the power connection from cabinet and directly short-circuit(ed) the power-pins (POWER SW pins as manual says it) of MOBO to make sure that power-supply button has problem or not. The proble still remains same.
  
• On the empty MOBO, I changed the PSU. Problem remains same.

There is one strange thing. If I do reboot using reboot command, it reboots fine but if II shut off and then boot using power button then again I have to use Reset button to start the computer. So, from all this what I am left to deduce ? .... Is MOBO gone or the UPS is culprit ?

[arnuld_aqua]

I have checked the UPS too. No luck. Here is something new I did:

• I used the shutdown command rather than poweroff and then system waits for me to power it off. Then I kept the power button pressed for 10 seconds and it powers the system off. I reproduced it many times.
  
• When I turn on my machine, as I said I have to use power and then reset button, then when I get to the BIOS screen, I can simply turn it off using a single press on power button, I don't need to keep it pressed for 10 seconds to power off.
  
• When I have used the power buton without using reset afterwards, machine does not turn on (you know it already). I can turn it off by holding the power button for 10 seconds.

[arnuld_aqua]

One more update: Yesterday, a strange thing happened. Suddenly, everything on my system got frozen. I gave command <b>top</b> to see what is eating CPU and I got this: I/O Error. I tried running firefox but again system was unable to read the disk. Even when I pressed Ctrl-Alt-Del the system froze in the middle while rebooting. I did a hard reset and then system hung up at BIOS POST message, I reset it 4 times and agian it always got stuck at BIOS POST. AT 5th time it booted but then hanged halfway in the middle when system was starting up. Something came to my mind and I replaced the PSU and at first boot it started working, no I/O errors. I left the system running overnight and in the morning it was still running fine. So I conclude this:

1) MOBO is fine, its the PSU who fried the MOBO
2) PSU itself may not be the problem. It could be the UPS who is sending wrong voltage to PSU and then PSU got corrupted which then corrupted the MOBO.

but how UPS got corrupted ? My system was couriered from 2000 KM away to here and in the process my cabiniet was broken because of extreme phycial shocks given by poor Indian courier compnaies (Well, I can't afford DHL, it is 10 times expansive than normal courier )