Turns out that after moving, my computer got damaged somehow. I installed my computer 2 days ago. I didn't check the state of the hardware parts and turned the pc on recklessly, not realizing that the cpu fan was dettached from the cpu. After this I reattached the fan. The computer worked kind of faulty after that, because at the time of startup, it would play a long beep (different from the normal beep) and won't display anything. I tried restarting after this incident and it got fixed (don't know how, but it did), and I was even able to play some videogames for some hours (more than 5).

This morning I tried to get this issue sorted out by checking again the cpu and in general, the connections, and for my surprise, at the time of turning it on again, the computer wouldn't boot at all. I reapplied some thermal paste to the cpu and fan, but got no results (I did this because the old paste was very badly distributted along the surface of both cpu and fan). Now every time I turn it on, the computer acts randomly:

• sometimes at startup, it plays a long continous beep and then turns off.
• one time it played a long continous beep and got to the windows password input screen, but then it turned off
• More frequently, I turn it on and after some seconds, it turns off without any sound.

You can check this video I recorded, which features how the computer behaves most of the time

Another one

I tried troubleshoting it myself by disconnecting my graphic card, rams, HDD and even the cpu and its fan with no result.

Computer specs:

Intel Core 2 Quad Q6600 processor, Nvidia xfx gtx 260 black edition, 4 GB ram, 500 GB hard drive, Windows 7 64 bit