I have read dozens of posts like mine but none of them are quite the same so I decided to post this and see if any other members could shed some light on the situation.
About 5 seconds after the computer turns on the fan on the video card speeds up really high and then the entire system powers down and all fans shut off.
I decided to disconnect the power cable to the video card and boot up to see if it would produce a different result.
With the video card not connected to the power supply, the system turns on and stays on. All fans spin including the video card fan and it does not speed up.
It is connected with a 6 pin Molex and when that is not connected the system boots fine.
However, I can not get any monitor to work with the built in motherboard video so I can not get a display on the monitor to access the bios.
I am relatively new to building computers (this is my first one) and this is the first boot after installing the system. I referred to a very thorough guide while building it and am nearly 100% sure that all cables are connected properly.
What could be causing this issue? is the video card bad? Is it not compatible with the power supply?
Im using a AMD Athlon II Multi Core Processor, a Gigabyte A55M-DS2 Motherboard, a Sapphire Radeon HD 6770 Video Card, Corsair Vengeance 8GB DDR3 Ram and a Cooler Master Extreme Power Plus 500W power supply.
When the video card is hooked to the power supply, right after the fan spins up and right before the unit shuts down the monitor will display the motherboard screen that says press delete to enter bios. But it instantly shuts down the second the screen flashes.
In addition, when the video card is hooked to the power supply I get 1 single beep.'
All the research ive done has concluded that 1 beep means everything is working great and post was successfull. Yet, right after that beep it shuts down.
I have tried reseating the card a few times to no avail. Im willing to try a different card... but for some reason I am convinced there is nothing wrong with the one thats in there.
With the video card completely removed and the monitor hooked up to motherboard video, The computer does NOT shut down. Instead, the computer makes a long beep that stutters at the end. The computer stays on and all fans spin, the computer stays virtually silent but the monitor displays no signal and will not display a screen.
Its unlikely to be the graphics card itself . If it was faulty there would be BIOS beeps as the machine booted .
I'd suspect the power supply . Despite the hype that psu is old junk . The little red voltage switch tells us that it was probably deigned by Fred Flintstone and is still be assembled in Bedrock .
Only use 80+ rated PSU's with a feature called "Active PCF"