Ran a similar spec machine to simpleton's on a quality 450W psu before, so 550W would be my recommendation too. Gives you a little extra for future additions to the system. Note that not all PSUs rated to xxxW will actually perform to that output under load. It's worth investing in the quality brands such as Corsair, Antec, Enermax and a few others. It's worth the little extra to get something that will definitely do the job.

My machine was running a Core2Quad Q6600@3Ghz, 4Gb Ram, Nvidia 8800GTX, 500Gb 7200rpm HD. Later it ran an ATI 5850 1Gb card.. all on a Shuttle 450W PSU.

Arctic Power is a rubbish low-end brand. Invest in a better quality PSU; be Quiet!, Antec, Corsair (except the CX series), Seasonic, Silverstone, Seventeam, Etasis, Zippy and OCZ are some of the good brands to consider.

Thanks guys but I dnt have the money ATM so the arctic power was all I could afford. I will look into get one of those higher brand psu's in a couple of months.

Cheers

How to eliminate the PSU as a suspect part? Is it shorting?

I have recently encountered a problem with my desktop and some people have suggested that it may be a short started in the PSU, going via the case, and into the ground contacts of the Mobo.

Is there any way, through the use of basic tools and gadgets i.e. voltmeter, tongue etc, to tell if the problem is originating with my PSU or if it is putting out power perfectly normally and fully isolated.

For your info I have an Enermax Liberty 500W which is 4 years and 9 months old.

I really don't want to bin 3/4 of the components and buy a whole load of new kit, so to eliminate the PSU as a problem would be a great help.

Cheers,
Tom.

If you have the slightest concern about the PSU, replace it. Don't even hesitate with one nearly 5 years old!

Could I not, to see if there is any Voltage leaking from the casing, take my Voltmeter touch one electrode to the PSU case and the other electrode to the house earth connection and see if there is a short i.e. a flow of electricity?

Tom.

I have an ATX power supply on the bench that shows 120 Volts on the supply's case, when isolated from the computer. One of the filter capacitors connected to the 120 v line is shorted...
Tommygunn, just replace the power supply

I bought an Enermax Modu87+.

Tom.

So the computer is working fine now?

Well, yeah, after I also dumped the MB and RAM to be be on the safe side..

Tom.

One of the most important pieces of hardware on your computer is your power supply. It runs power to the other components of your computer by switching the power that comes from your outlet (AC) to the direct current (DC) which your computer needs. Without it nothing else would run and a poor quality or failing power supply can potentially put unwanted strain on expensive computer parts and components.
A minimum of 550 watts to 650 watts for high end desktops.

Wattage is among the least important aspects of a power supply. If you are using a basic desktop, the power supply doesn't matter much. But if it is a computer you care about and plan to keep for a long time, or use for gaming, photo editing, or design work, you would benefit from reading up on power supplies so you know which ones are good, and what the minimum requirements should be.

I'm glad you said this Raybay... Everyone thinks wattage is the first thing to be considered, but we know differently. We know good brands and not so good brands, and models like eMachines and older Dell's have had plenty of power supply issues

Another reason to be wary of unheard-of PSU brands: Fake PFC circuits.

Check out the story here.

http://www.extreme.outervision.com/psucalculatorlite.jsp