So, I finally took the computer to a tecnician.
The problem, as I was told, was the power input of the video card. He had to do something with the BIOS too.
the computer is back to life, but not as before. I do not have some basic functions, such as the auxiliar buttons that sleep the screen, or the functions shortcuts of F1-F12. My touchpad doesnt answer to multiple finger commands and the computer is very slow to start (When I bought it it would take 24 seconds to boo. Now it is taking over 2 minutes....)
The worst part: I could not run the system detect, neither instal the Dell Rapid Start.... For the rapid starts, I get an error saying that the computer doesnt have minimum system requirements...
Since there's no video card in the system -- it's a chip that's part of the mainboard -- there's no way a technician could have changed that.
It sounds like a Windows reload was done incorrectly - minus the full set of required drivers. Are there device manager entries missing their drivers?