My computer works for only 3 seconds and then shuts off what is the problem?

[nessell]

My Computer tries to start but shuts down after 2-3 seconds what is actually the problem?

 

[italstalpf3]

My Computer tries to start but shuts down after 2-3 seconds what is actually the problem?

Might be a faulty power supply. I had that issue before and I bought a new powersupply and the problem was solved. Also make sure you have everything inserted properly.