I took out the harddrive from this computer and put it in another computer to install windows in it, I installed it succesfully. Also i took out the ram just to see what kind of ram it uses and then i put it back in.
Then i put the HDD back into this computer and when i turn it on it Beeps and don't show Bios screen or anything but it turns on.
I checked all cables and they are all connected, I don't know what to do or what does it mean.
Unplug everything that isn't needed to boot up. Leaving the Ram, Videocard, CPU and of course the power supply still connected to the mobo. See if it boots up then.
If not since you did mess with the ram try taking them out and placing only one stick at a time if you have more than 1 (can't see in the video). If it boots up after this try putting the other ram stick /'s back in.