i just put together a pc for the first time , and everything was up and running , now i'm having power issues. my mb light is on but everything else is dead, just want to be possitive before i replace my psu.. any info would help..thanks

You have not supplied enough info. We need - make and model of the mboard, or - make and model of the brand name system - cpu model - power supply make, wattage capacity - graphics card (in a slot) make and model, if that applies Generically........ - if you are using a graphics card, or cards, in (a) slot(s), the PS must meet or exceed the minumum required system PS capacity, and if stated, that AND the minimum required current at 12v. Go to the web site of the maker of the video card, and look at the specs for the model - it will probably say in the specs somewhere what the PS minimums are - often that's under system requirements - if you can't find that any card with the same video chipset has very similar PS requirements - if you have a Phenom cpu, AM2+ earlier models, and probably AM2 models, cannot handle the Phenoms that require more power, despite the fact they can handle 125watt Athlon 64X2 cpus - they are limited to supporting 85 watt Phenoms max. You will fry the mboard circuits in a short time if you install such a Phenom on such a mboard. In that case you must use a AM2+ mboard that is rated in it's specs to handle a 140 watt (Phenom) cpu - if you don't see that it doesn't. - if you bought an el-cheapo PS, or a case with an el-cheapo PS, the PS is a lot more likely to fail than a better more expensive one that has the same or similar wattage capacity, and while it's failing it's a lot more likely to damage something else, e.g. often the mboard. ......... Failing power supplies are common and can cause your symptoms. Check your PS. They often partially work, fans and hard drives may spin, leds may come on, yet you get no video and the mboard will not boot all the way. See response 4 in this: http://www.computing.net/hardware/w...

i appologize for the lack of info i'm just a bit aggravated at this point. i'm using a asus mb M3A78 and an amd dual 5800 3.0 my. come to think of it i only payed 20 dollors for my power supply. it was a green 680 watt20+40pin atx w sata ans pci, and 1 more question how much power is actually needed , i'm not into gaming , i just plan to burn movies , and watch movies on my pc.. thanks again

"come to think of it i only payed 20 dollors for my power supply." That's one thing it's never wise to scrimp on The one thing that is likely to be of worse quality that in the past is el-cheapo power supplies. Their max specs are often a lie, and not only are they a lot more likely to fail, they're a lot more likely to damage something else when they fail, often the mboard. A good PS - has a brand name well known to make decent quality PSs. e.g. excellent - Antec (3 year warranty ones are better) , Enermax, Thermaltake; middle of the road - Coolermaster, others who also make cpu fans, cpu heatsinks, the brand Tigerdirect has the most models of; cheaper but good quality - A-Open, Startech, Sparkle and many others - of the same capacity costs more - has a decent web site for the brand - has at least a 1 year warranty, better still a 3 year warranty or a lifetime warranty - you may have to look at the model's specs at the brand name's web site to find that - weighs more because it has heavy duty components - that often also results in the PS runs cooler - has anti-short, over-voltage, and anti-overload protection that automatically shuts down the PS, and usually that results in no damage to anything else - has (a) fan(s) with two ball bearings, note the s, or better, not one ball bearing (note the no s) and a sleeve bearing, or two sleeve bearings - two fans are better than one, but a larger single fan is okay - is a lot less likely to damage anything else it it fails "asus mb M3A78 " As I recall, that mboard model is rated to support up to 140 watt (Phenom) cpus, so you can use any AM2 (940 pin) Athlon 64X2 or Phenom cpu the the bios version supports - see the cpu support info for the model on the Asus web site. I'm going to be using a M3A78 Pro for a friend's system soon, and I know it supports 140 watt cpus. "how much power is actually needed" See response 1 - the system PS must have at least the minimum ratings that supports the video card in a slot you are using or might use in the future. If you think you may upgrade that in the future, currently a 600 watt or so or greater PS that also meets the current requirement at 12v will support a system with a PCI-E X16 card with any video chipset in a single PCI-EX16 slot, even if it is a X2 card (two video chipsets on one card), or two single video chipset cards in two slots. (Nobody needs a 1000 watt PS, even if they can install 4 video cards)