Failing to Start up

[BadBoyJH]

I am trying to re-work an old PC to work as a Media-PC, I have very low quality movies, and this isn't the issue, so don't tell me to get a proper computer to do it.

Its an Acer Aspire A60 (yes its 10-ish years old), and When I plug it in, it starts the normal start up proccess, before it can put anything onto my screen, it stops dead. Power button will do nothing, and its like the power has been cut.
Unplugging and re-plugging in straight away does nothing, requires a 15 second delay without power to try again. I have tried the ram, and it doesn't seem to be the issue. Power is cabled correctly, and everything else is in order.
Is it the power supply, and where is the cheapest option to replace it, considering I can't buy on internet (Don't ask), and there are some computer fairs here (In Newcastle Australia), over the next fortnight (2 weeks).

 

[Slaymate]

It could be a number of things. Have you cleaned out the dust lately? Are all the fans working? It could be overheating.

Does the computer Beep? If any component is bad it could short out the system. I mean any component from a dc/dvd drive to the video or cpu.

It could be a power supply issue or a problem with the power circuitry on the motherboard.

With a computer this old you may wind up spending more money trying to fix the problem than you would buying a new computer.

 

[BadBoyJH]

There is dust in the Power unit, but without opening that up, I can't clean it any more. There are occasionally beeps (by which I mean it sometimes stay on for long enough for the computer to continually beep at me, before going caput.

The Power Fan spins, and the CPU fan spins, but that's all I have seen it do, it may be the ram, which I had sitting fairly unprotected out of the box for a while is it worth buying a stick of 1GB DDR Ram (That is the type of ram), because it was suggested to me that it might be the ram.