PC reboots, no video

Hy guys,

I'm having a situation here:
I shut down my PC without problems, but now it does not boot anymore.

When I firstly tried to start it up it simply did not show anything on the screen. I reset it and it started beeping: 3 long beeps rounds. I cleaned the RAM and placed it back.

Now it does not beep anymore but it neither shows anything on the screen. However, it automatically resets after about 1 minute. I also noticed that the CPU fan starts, it stops for a few seconds and after that sometimes it remains stopped or sometimes it starts back.

I checked the RAM with another PC and it's working. Could it be the video card (it's cooler is working) ? Or the battery ? What should I do next ?

Thanks.
 
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