my computer wont boot up i just keep getting flashing lights and

[tolpo]

when i try to boot all i get is four intermittent beeps with  a redlight that flashes four times with it, it does this around five times and then just the flashing continues, when i bought it, the seller said it had no operating system but i cant even get into the bios because the  computer screen wont even register a device. does anyone know how to activate it.

[TheOldMan]

Here is the manual for that PC

http://h10032.www1.hp.com/ctg/Manual/c04327174.pdf

page 141 has that error code and the possible solutions.

this is what is recommended

1. Open the hood and ensure the 4 or 6-wire power supply cable is seated into the connector on the system board.
2. Check if a device is causing the problem by removing ALL attached devices. Power on the system. If the system enters the POST, then power off and replace one device at a time and repeat this procedure until failure occurs. Replace the device that is causing the failure. Continue adding devices one at a time to ensure all devices are functioning properly.
3. Replace the power supply.
4. Replace the system board.