My computer starts and 2 seconds later beeps and shuts off

[JDV19750525]

As I start up my desktop, I will hear soft beep noise and later little bit harder beep noise about 3 - 4 seconds. Then the pc will shut down again. You have to sometimes start the pc 9 times before login. Sometimes with the first attemp it works. I will disconnect the cd writer's power cable and sometimes it will start up. I've replaced the memory (1.49gig of ram) and still doing the same. Could this be the power supply?

 

[weaselman]

I dont know how old the system is, but if its new with a new graphics card in it and its a Pci-e graphics card, the four second beep means the card is not fitted correctly in the slot.
So you will need to to open the case and check if the card is fully in its slot.
The other one could be the card complaining it has not got enough power to run, but i suspect it is the first opinion I gave to you.