Hi, I have a HP Pavilion 424.uk desktop PC. For some time I have been using it with a GeForce 6800 XT (for about 6 months) and have had no problems (although a noisy fan from inside the computer it appears now may have been the graphics card fan.)

A few days back I was using the computer and it suddenly cut out. Whenever I tried to turn the computer back on it would make a buzzing noise for a quarter-second and then cut out. The computer would not come on. If I took the power supply cable out of the back and reconnected a couple of times, then the green LED would sometimes light up again, but attempting to turn the computer back on would result in the same short buzzing sound, and the green LED would turn off again.

I opened the computer up and started removing the parts. After playing about I found that I could restart the computer if I used the on-board graphics slot, or if I changed the graphics card to an older card that came with the computer. As long as I did not have the GeForce 6800 XT connected to the power supply the computer would work, it just would not work with this card.

So I am using the computer now with the older graphics card and it is working fine, although I had to reinstall Windows XP and therefore lost all the data on my harddrive

The question then, is this a problem with the power supply or with the graphics card? It seems possible that either the graphics card will no longer work and is stopping the computer from working, or the power supply is no longer working well enough to power the graphics card along with everything else connected.

I should also note that the graphics card has been heavily used over the previous 6 months, as I have been working very long hours running a business in a virtual world, and also, the power supply has also been worked heavily over the 3 years I have had the computer. Luckily the graphics card is still under warranty.

Also, if you think that it is a power supply problem, and that I should try changing the power supply, then I would love some advice on what other power supply I could buy. I took the power supply to a local computer store and the clerk there told me that it was a non-standard power supply that would be very expensive to replace. He then told me that I was better off buying a new tower, but I must admit that I don't have full confidence in the clerks at that store because they have tried to trick me into buying more than I needed in the past, (and that time I knew that they were trying to trick me.)

Thanks for any advice or help beforehand. : )

it could be a faulty graphics card or the power supply is not powerful enough

what size power supply have you got?

Hi, on a sticker on the inside of the computer it says that the maximum output of the power supply is 200W (maximum.)

what size memory has the graphics card got?

run this and it'll tell you how much power you need

http://www.journeysystems.com/power_...calculator.php

I did the calculations and found that I require a new power supply, even though the computer had been working fine without one up until now. The power supply calculator says that I require a recommended power supply of 325 watts minimum.

The problem with this is that I don't know what power supply I should get, or even what to look for when buying one to ensure that it will fit my computer's case.

You definitly need a larger PSU. 400W minimum.

As to the spec:

http://h10025.www1.hp.com/ewfrf/wc/p...299100&lang=en

It appears to take a standard ATX PSU:

http://h10032.www1.hp.com/ctg/Manual/bph07989.pdf

Hi,

I got onto HP support chat service and they gave me some advice. Here is what they claim I should be looking for:

Micro ATX power supply.
(must fit turbolite chassis).
20 pin power connector.

350 Watt minimum; up to 400 Watt maximum.

Also this lot from the second time I spoke to them:

"input voltage - 110V - 230V • max. output wattage - 124W, 149W, or 200W An ATX12V-compliant power supply is required to supply supplemental power to motherboards with Pentium 4 processors. Always connect the additional +12V power connector to the motherboard.

Do not use a standard ATX power supply on Pentium 4 based systems. Damage to the board and power supply may result."

I would go for the 400W. When I said "standard" I was meaning an ATX 12V compliant PSU. My "standard" does not go back pre-P4 when I guess the "standard" was different.

All that being said the important thing is the "Micro-ATX" Form Factor.

Here is a starting point:

http://www.google.com/search?sourcei...x+power+supply