Pc not booting

Hello,
I am using a dual core pc for the last 6 years. It was quite good before this problem. After giving power to the pc all the fans start spinning. But when I try to turn on my pc, it doesn't response. The fans are spinning slowly and mouse light is low. Keyboard light doesn't on. Monitor shows pc is on but nothing in the display at all.

I am using..
G41 m7 intel biostar motherboard
Ddr 2 800mhz 1gb ram
Intel dual core 2.7 ghz processor
No external graphics.