Pc won't open when i switch power on.

Hello,
i have old gigabyte GA-8ILMT4 motherboard. When i placed 128 mb ram on it, it didn't work. I have already 256 mb ram on it. After it i removed 128 mb ram and start the pc. Pc doesn't start (no beep sound). Moniter was on but no display. Green and red light was on.
After it i do reassemble it and i do clear cmos by jumper on motherbord.
Then i start pc. It won't start. When i press on button cpu fan rounds 5-6 times then stop. Pc remains off.
What should i do.