serveral days my computer just got a problem.
Its monitor won't display anything even though my computer is on.
(LED green light on the monitor is keep blinking, even though the comp is on)
Also, there is no beep sound when it happens.
So I have to turn my computer on and off (also restart (reset button) many times. and sometimes (rarely) When monitor starts to display, it shows that my cpu is overclocked at the wrong speed (1100 instead of 2500). I have to either re-overclock or press restart button in order to get CPU running at the correct speed.
It's like 8 out of 10 times (that) my monitor won't display anything even though my cpu is on.
I also open my computer case, checking fan, heat sink, power supply.
They're working fine. Heat sink and CPU fan is actively running. Power supply is working. Green Light on motherboard is on.
I also unseated and reseated graphic card. It wouldn't work.
I tried reseating RAM. It did work for a while then the problem came back.
I haven't updated or changed any setting on my computer before this happened.

Here is a specification of my computer
PSU 300watt
Motherboard: ASUS A7N8X
CPU: AMD Athlon 2500+
Ram: 2 GB DDR
OS: WIndows XP SP2
Graphic Card: nVidia GeForce FX 5200 128 MB

Any one know how to solve this problem or having a similar problem?
Thank you

try a diff monitor if you can, or try a diff g-card? let us know!!!

I tried a different monitor and different graphic card.
It didn't work.
I also tried to reset CMOS. It didn't work either.
Any suggestion?