Got a old AMD based computer that only starts every other time, it doesn't restart either.

When attempting to start the screen does not display bios information just a blank screen, all the discs fire up though. When I hold in the power button and retry it starts up as normal. When attempting to restart windows shuts down properly but the hardware keeps running and again a blank screen. I then need to power down manually.

I have tested the ram and gpu in other computer and used other gpu/ram in this one and the same symptoms occur.

I have updated the bios and the same symptoms occur, the only things I have been unable to to test are the cmos battery (replacing soon), the cpu and motherboard.

Anyone have experience with something like this and can say if it's worth continuing trying to remedy it or is it a lost cause?

If the motherboard or cpu needs to be replaced (this is what I fear) I will just bin the pc as is it not worth spending a large amount (any at all for that matter but a 50p cmos battery wont hurt) of money on.

Thanks again you clever lot you

I have updated the bios and the same symptoms occur, the only things I have been unable to to test are the cmos battery (replacing soon), the cpu and motherboard.

What about the power supply? Here's my canned text for testing PSUs:

To properly and conclusively test a power supply unit (PSU), it must be tested under various realistic "loads" then analyzed for excessive ripple and other anomalies. This is done by a qualified technician using an oscilloscope or power analyzer - sophisticated (and expensive) electronic test equipment requiring special training to operate, and a basic knowledge of electronics theory to understand the results. Therefore, conclusively testing a power supply is done in properly equipped electronic repair facilities.

Fortunately, there are other options that are almost as good. I keep a FrozenCPU Ultimate PSU Tester in my tool bag when I am "in the field" and don't have a good spare power supply to swap in. While not a certain test, they are better than nothing. The advantage of this model is that it has an LCD readout of the voltage. With an actual voltage readout, you have a better chance of detecting a "failing" PSU, or one barely within specified ATX Form Factor Standard tolerances. Lesser models use LEDs to indicate the voltage is just within some "range". These are less informative, considerably cheaper, but still useful for detecting PSUs that have already "failed". Newegg has several testers to choose from. All these testers contain a "dummy load" to fool the PSU into thinking it is connected to a motherboard, and therefore allows the PSU to power on, if able, without being attached to a motherboard - great for testing fans, but again, it is not a true load or suitable for conclusive testing.

Swapping in a known good supply is a tried and trued method of troubleshooting, used for years even by pros. If you have access to a suitably sized, spare power supply, carefully remove the suspect supply and replace it with a known good one and see if the problem goes away.

I do not recommend using a multimeter to test power supplies. To do it properly, that is, under a realistic load, the voltages on all the pins must be measured while the PSU is attached to the motherboard and the computer powered on. This requires poking (with some considerable force) two hard and sharp, highly conductive meter probes into the main power connector, deep in the heart of the computer. One tiny slip can destroy the motherboard, and everything plugged into it. It is not worth the risk considering most multimeters, like plug-in testers, do not measure, or reveal any unwanted and potentially disruptive AC components to the DC voltages.

Note the required voltage tolerance ranges:

And remember, anything that plugs into the wall can kill. Do not open the power supply's case unless you are a qualified electronics technician. There are NO user serviceable parts inside a power supply.

a fair point sir, I had completely neglected the PSU, thanks for the hint I have another one I can test with,

Thank you very much for the really useful information Digerati.

I have another one I can test with,

Keep us posted.

I swapped out the PSU and put in a nice fresh CMOS battery (BIOS mentioned 'CMOS battery low' every now and then when booting) and the symptom remains the same so I can only deduce that either the motherboard or CPU has a problem and needs to be replaced and seeing as it's a 1.5ghz machine then I don't believe it to be cost effective and therefore will salvage the ram, psu, drives etc. and bin the board.

It's just far to slow and old to justify spending any money on.

Thanks for the advice though, because the PSU had been replaced in the last few months I completely overlooked it, that isn't to say of course it couldn't have been the issue, and the above information is very useful for future troubleshooting.

Well, sorry we could not fix it, but I think you are right with your diagnoses. Thanks for the followup.