Computer won't start; Diagnostic help please

[supercharger]

This is my first time here so hopefully i give you guys enough information without sounding like an idiot.

My system:
AMD Athlon64 bit processor with ASUS mobo
4G SDRAM
500G HD
600W Antec power supply
dual SLI video cards- nvidia 9800 series i think (I always forget so if that sounds wrong just be aware it's definitely dual cards)
I run a USB keyboard and mouse- logitech G15 and G6 respectively.

My problem goes like this, i'll try to be brief:
I have been getting error messages for several weeks saying "insufficient power to video card" but i've always felt the software for the video cards was kind of goofy so i just ignored it (which was porbably a mistake looking back on it). Two nights ago I start my computer and login to windows Vista (this tells us my USBs were working at startup since i had to type in my password). I leave the room to make some delicious nachos and when i come back my USBs are all dead. I took the case off and vacuumed out the dust (after unplugging and disconnecting all external cables). When i tried to start it up again the indicator light on front of case comes on for about 5 seconds then unit shuts itself back off. Assuming the power supply to be the issue (because of the errors i had been getting) I purchased and installed a new thermaltake 850W last night. Problem still persists...

It seems like I've seen this recent symptom before with a shorted motherboard but just thought I'd get the opinion of the pros. Thanks in advance for your help.

[JJ 3000]

I took the case off and vacuumed out the dust

bad idea...

from http://www.computerhope.com/cleaning.htm#02

Sucking the dust, dirt, hair, cigarette particles, and other particles out of a computer can be one of the best methods of cleaning a computer. Over time, these items can restrict the airflow in a computer and cause circuitry to corrode. Do not use a standard vacuum as it can generate a lot of static electricity that can damage your computer.

[supercharger]

lol, i tried not to sound like an idiot and unfortunately misrepresented myself. I did not use a vacuum, but rather blew the dust out manually (without any sort of electrically apparatus, use your imagination). sorry for the confusion.

[patio]

With dual cards you may indeed be short on power...

See Here...

[supercharger]

As I stated originally I have already replaced the original power supply with a brand new thermaltake 850W so I don't think it could be a power issue, unless you think 850W is still much too low (though it did run OK with a 600W Antec for several months before this all happened).

[Computer_Commando]

Exact make & model of video cards?

[supercharger]

here are the 2 video cards i'm running:
ASUS EN9600GT/DI/512MD3 GeForce 9600 GT 512MB 256-bit GDDR3 PCI Express 2.0 x16 HDCP Ready SLI Support Video Card
ASUS EN9600GT SILENT/2D/512MD3 GeForce 9600 GT 512MB 256-bit GDDR3 PCI Express 2.0 x16 HDCP Ready SLI Support Video Card
 both purchased new from newegg 1 year ago.

[Computer_Commando]

Unlike other manufacturers, Asus provides no specs for power requirements.  Should say something like:  "+12VDC @ xx Amps".
On the PSU you have, what does it say for the +12V?  Probably has two:  +12V1 & +12V2.  Each should be at least 30A, 20 for each card & 20 for the motherboard.

http://usa.asus.com/Product.aspx?P_ID=Vdj5eZL6xdbO0KB6&content=specifications

http://www.asus.com/Product.aspx?P_ID=kgHu9nSBfyqksBix&content=specifications

If you still have problems, remove 1 video card & see what happens.

[supercharger]

here's the output amperage info for the new power supply installed after this problem began: Output +3.3V@25A, +5V@25A, +12V@69A, [email protected], [email protected]
and the page on newegg: http://www.newegg.com/Product/Product.aspx?Item=N82E16817153106

[Computer_Commando]

Specs differ from description:
+12V@69A  is not the same as:  "...Toughpower has four separate +12V rails so you're guaranteed crisp, clean power delivery. Each one of these four rails can handle 18 Amps of overload before a safety shutdown occurs..."

According to Thermaltake, there is only one +12V rail.
"...Robust and dedicated single +12V output provides superior performance under all types of system loading...."
Specs say nothing.  Label in pic on Newegg says +12V@69A
That's a lot of power but between 2 cards and an AMD mobo, you could be near the limit.

Did you try the PSU calculator?  http://www.thermaltake.outervision.com/

[patio]

In your original Post you stated 600W Antec...
Now you say 850 Thermaltake...

Which one is it ? ?

[supercharger]

commando- I did not try the PSU calculator, Thank you for pointing that utility out to me and i'll give it a shot.

patio- please reread the original post and you will see that it is actually both since the power supply was changed last night, before i ever posted on here. ( I only listed the Antec 600 so you guys could see that I attempted to rectify any PSU issues before posting here, sorry if I didn't make that clear)

[patio]

No problem...i happened to miss it...