UKC

Pc was working then would only turn on after a few attempts now not at all.
I've tried replacing : ram, CPU, motherboard, PSU, cleared bios, disconnected HDD / dvd drive and peripherals, tried onboard graphics instead of graphics card. All fans spin, drives spin but no beeps, nothing. I'm totally stumped.

In reply to The Potato:

you say you've cleared the bios therefore the hardware is working allowing to boot to bios, i.e motherboard, ram, cpu and psu.
i would try to see if you can boot to an environment other than your hdd. A windows boot disc, linux disc, boot usb etc, if able to boot with something like this then look at the hdd as the culprit.
if you are able to, get your hdd connected to another pc (as a slave) and back up your stuff if poss

In reply to wilkie14c:

No I've cleared the bios/CMOS whatever it's called by using the jumpers, as I say it won't load to bios screen and I don't get any beeps at all.

In reply to The Potato:

if it is t even booting to a bios on screen then there is obviously a problem, most likely a power rail is missing preventing it from getting into an S0 state (system on) without a schematic diagram and the tools and know how to all the power rails it sounds like a no hoper. Motherboard repair is unviable unless it's an apple product so imo the best option is another board off ebay of the same model, that way there are no ram, cpu and driver issues

In reply to The Potato:

It would have been cheaper to steal a complete new computer

In reply to wilkie14c:

Umm ok but as I say I've already replaced the motherboard

In reply to The Potato:

ah missed that sorry!

In reply to The Potato:

Did you plug it in and turn the power socket on?

In reply to The Potato:

You seem to have replaced the entire computer, and yet it still "won't boot"...

How are you determining this non-boot?

Have you unplugged all PCI/PCIe cards?

Have you tried another monitor?

In reply to The Potato:

I know virtually nothing about PCs. However I have experienced the same symptoms more than once ie failure to start, then starting next day, then failing again and nothing.
It was what I think is called the clock battery (the coin battery) and just replacing this did the trick. It seemed similar to the behaviour of an old torch battery which can recover for a short period if left.
This is probably complete rubbish.

In reply to captain paranoia:
Monitor is fine, even if it were fubar the pc would still make a single beep and the fan speeds would drop after entering bios.

Only pcie card is graphics

In reply to oldie:
Well I'll try this however after replacing motherboard it comes with a new battery so I doubt it, worth a go though!

Edit, cr2032 battery was quite flat but new one didn't do anything else.

The only thing I've not replaced is the case, LEDs, speaker! Wtf?

In reply to The Potato:

If you've swapped *everything*, and still the thing's not working, then something's fishy. My suggestion is to slow down, and go back a few steps. Are you *sure* that all the parts you've swapped in are themselves good? How are you testing each part? Etc.

Good luck! Let us know how it turns out.

In reply to oldie:

I was also going to suggest the internal battery. My pc experienced the same problem yesterday ( although I'm getting 6 beeps) so I'm going to try a new battery before anything else.


OP: good luck, I'll be following this thread closely.

In reply to The Potato:

It'll be a dirty/dodgy connection somewhere.
I had a major crash a while back, ended up getting a new (2nd) drive, and they now just sit on top of the case, I can't be arsed boxing it up all again.
Sometimes it doesn't boot up, so power off, re-seat the data cables, power up ... works fine.

In reply to The Potato:

Have you tried turning it off and on again?

In reply to The Potato:
Took everything out of the case and assembled on wooden table incase it was shorting on the case, tried different parts, nuffink. I'm wondering whether the replacement MB is also defective. This is just too odd.

In reply to The Potato:

Have you got any LEDs lighting up on motherboard?

Are you absolutely certain the CPU is inserted in correct orientation?

The things you are using to swap with are they brand new components or components that have been working in another PC or 'questionable' components that you aren't totally sure about?

When you 'cleared' the BIOS and/or messed about with jumpers did you do that on both the original and the 'replacement' motherboard or just on the original?

In reply to tom_in_edinburgh:

i concur
the status of the "known good" components is in doubt unless they are actually seen to been working just before substitution

In reply to The Potato:
Turns out the 'tested' motherboard was defective, whew thought I was going mad
Thanks for the suggestions