Laptop will not start, no fan noise or hard drive noise

Laptop will not start, no fan noise or hard drive noise

One day I was working on my latitude D620 and all of a sudden it just shut off. I tried restarting it, but when turning it on I only got the power icon light to turn on for about 3 second and then the light went away. Also when I try to turn it on I do not get a fan sound or a hard drive sound. It seems to me that there is no power going to the drive or fan. I have played with the memory modules but still not luck. Any ideas?