Computer Not Starting

Sorry I cannot give you any of the required info on my older desktop computer, it is a bitsa and not a brand name, has an Asus mother board, with I think an i5 chip, has both an SSD and a hard disk drive and also a replaced DVD drive, and I think it is about 11 years old.

The computer was working with no blue or black screens or any problem for that matter, I tried to turn it on a day later and it doesn't start at all, I have removed the 24 pin power pack connection and bridged pins 16/17 and the cooling fans runs as per test, -- with the side cover off and when I press the start button, the cooling fans will start to spin and then stop, there is a green LED on the mother board and this is constant green.

The unit has a 4 wire push button on/off switch, would it be ok to bridge the 2 start wires, or would this create a short, I am not familiar with computer switches, but ok with automotive, would there be a schematic of a 4 wire computer switch that I could have a look at?.

I am thinking the problem could be the switch, any other ideas someone may be able to help me with?.

Thank you in advance.

 

The usual power switch is just two wires to the motherboard jumpers (this is a generally speaking) and shorting them is what a switch actually does, that said I've never seen four wires.. like a double pole double throw switch? The case would usually have a normally open momentary switch to power on, or some older ones might have a latching switch (stay down when pressed, releases when pressed again).
Anyhow, with the specs you've described it sounds like this PC is not that old...
Grab the mobo manual from Asus and see what pins on the board are for the power button and briefly short them & see if it comes on.

1) Pull the power plug, push the power button, then plug it back in and hit the power button.
2) Unplug USB devices, keyboards, mice, leave only the monitor - repeat step one.
3) Open case and remove any cards, RAM, SATA/IDE from MOBO - so you have the front connectors, CPU , cooler, mobo power 24pin (any extra mobo power) and monitor connected - repeat step one.
If it is still dead, you can try a new power supply, remove all the remaining parts from the case and see if it boots on the table.

 

Thanks for your advise foogoo, I have a new 4 wire switch coming, the extra 2 wires are for the LED in the switch button, I had to ask the question though.
I can start pulling things as you suggest and do the tests.
As I mentioned, I removed the power supply 24 pin connector and bridged pins 16/17 as suggested and the power supply fan ran, it was said that if the fan runs during this test, the power supply is ok, what are your thoughts on this test foogoo?, I have asked this question for guidance.

This will be a slow process posing questions and answers on this forum, I have a near new Desk Top Computer that my grandson and I built some months ago, the older Desk Top has a lot of Data on it and I need to keep this running for awhile yet.

 

I mean shorting those pins and the fans startup is a slight test of the viability of that power supply, I've had power supplies that passed the 'test' until under load, then they fail.
You can get a power supply tester, usually under $20, before you buy a new power supply.

 

I removed the front panel yesterday and it seems like the original on/off switch is part of the panel, when the new switch arrives, I will have to drill a new mount hole for it, that is if I use or need to change it.
I have also bought a new power supply, this wont go astray if the original power supply hasn't failed, I will find this out when I get the new one and do a switch.

I will also look into the power supply tester you mentioned, it wouldn't be a burden to have on hand, seeing that there 7 desktops in our household.

I also pulled the CR2032 battery yesterday and this is reading 3.2volts.

 

I found the build invoice for the old desk top,
build date 9/01/2013
Had an i3 originally, I am sure I replaced this with an i5
Asus P8H61-M LE/USB3 LGA1155 MB
4gb Corsair DDR3 RAM module
550W ATX power supply
Gigabyte graphics card GV-N740D50C-2G1 REV:1.1
originally had a Samsung DVD drive, replaced that about 6 months ago, brand unknown.
Checked the battery again reads 2.9volts, I had the mains power turned off overnight.