PC is switched on only sometimes

[Gugollar]

PC : Acer aspire M5700, Windows 7 Pro. 32b.
Intel® Core™2 Quad CPU，DDR2 800 SDRAM 4G，GPU has been removed & use on board
Intel® G45，G45T AM2 V:1.0 motherboard，Hitachi SATA 3.0 7200rpm 500GB。

Used only now and then for internet only, and for storing some images.

Started a few monther ago, the power switch did not turn the PC on sometimes. And now it switches the PC on only sometimes.

Tried to short-start the PC, the same situation.
Tested the PSU and found it seems to be good because there is power.

Help, please.

Thanks.
Gugollar

 

[johnb35]

Did anything change from a few months ago when it started doing it? Like hardware was added or removed? So when you press the power button you don't get any fans running or any beeps? Sounds like a hardware issue somewhere like possibly ram. Try removing the ram and reinserting it, if you have 2 sticks try one at a time. You could also try resetting cmos by removing the battery. Disconnect power from power supply, remove cmos battery from motherboard, press and hold power button for 10 seconds, then wait 5 minutes. Reinsert battery, reconnect power and see if it will turn on. Note - any settings that were specifically set by you in the bios will need to be set up again as removing the battery will set it back to default settings.

 

[Gugollar]

Did anything change from a few months ago when it started doing it? Like hardware was added or removed? So when you press the power button you don't get any fans running or any beeps? Sounds like a hardware issue somewhere like possibly ram. Try removing the ram and reinserting it, if you have 2 sticks try one at a time. You could also try resetting cmos by removing the battery. Disconnect power from power supply, remove cmos battery from motherboard, press and hold power button for 10 seconds, then wait 5 minutes. Reinsert battery, reconnect power and see if it will turn on. Note - any settings that were specifically set by you in the bios will need to be set up again as removing the battery will set it back to default settings.

Thank you.
1. Did not change anything on the PC.
2. Replaced the CMOS battery 2 days ago. No difference.
3. The PC was disassembled for cleaning, even the PSU case, & assembled & started a few times.

 

[johnb35]

So are you saying you removed the motherboard from the case, cleaned and then reinstalled? The system could be grounding out somewhere and not starting. What I would recommend doing is remove the motherboard from the case set it on some cardboard and hook everything up so you can see if the system starts. This also could be a psu dying issue or possibly the power switch. This is a very old system and it just may be dying on you finally.

2. Replaced the CMOS battery 2 days ago. No difference.

If you did not follow my instructions on how to clear cmos then just replacing the battery may have not done anything. The system has to have the power unplugged and residual power drained by pressing the power button.

 

[Gugollar]

Thank you.

Please pardon me if I am wrong. I do not have much knowledge about computers. Based on what I have experienced, the CR2032, whether on board or not, does not affect power on or not. Is this correct?

What puzzles me now is that the power is not always on the Power SW pins. I have been trying to short-start the PC in the last few days, there is not always power on the Power SW pins

 

[johnb35]

Computers may or may not boot with the battery missing, we've seen it both ways. If you aren't familiar with diagnosing a pc then your best bet would be to take it to a repair place and pay the small fee to have it diagnosed. It very well may have breathed its last bit of air. Again, that's a very old pc.