My trusty old (6 years) desktop PC has been difficult to get to start for the past couple of years. I press the start button, the fans and HD's whirl, but no peep to prove it is booting. Leave it like that for a while, then force it to shutdown by pressing the button for ten seconds, once it is forced to shut down, press the start button again and it starts. Leave it for too long 'warming up' and it fails to peep and boot. Once started I dare not hibernate it, unless I don't intend to need it for several hours, because it would not restart. I can though successfully use a software restart for instance if new software needs the system to be restarted. Once running, it runs absolutely fine all day long.
As the weather becomes warmer, it becomes more tricky to get the 'warm up' period just right.
AS the PSU seemed the most likely issue I checked the PSU out when it was refusing to boot including the PG, everything seemed fine, but I tried another new PSU anyway, which made no difference - so I am now of the opinion that it is the motherboard causing the problem. To me, it seems to be thermally related.
I also tried adding a proper reset button, to the pins on the mb - that didn't help.
Today was one of those days when it refused to start, so I had another look at it. Guessing at the crystal failing to oscillate, I tried cooling that with a moistened finger tip and managed to get it to boot.
My PC motherboard knowledge is well out of date now, so maybe someone might be able to confirm I'm looking at the correct crystal for the motherboard + CPU etc.. I spotted two, one a familiar type used for the clock chip, the other is mounted direct to the PCB (no exposed leads), is very low with an oval top. Next to it is a surface mount IC and both are adjacent to the CPU socket. Close to both the above IC and the crystal there is lots of tiny (illegible) text. The crystal looks as if it is marked 148???? 148 Mhz(?). CPU is a dual 3Ghz.
I'm thinking to try replacing the crystal, after a bit more experimenting with cooling the crystal when it refuses to boot.
Resale value of PC = zero, but the effort of setting things up on a new system would be immense - so I would prefer to get this one fully working.