O.K guys. Thank you for your support and suggestions. Finally I've got it fix. The problem was in the Left I/O/ board. The first time I connected the computer it didn't work. It was doing the same as before. A dimmed blinking light in the mag. connector. Afrter i spoke with one of the guys, unfortunately I don't recall his name, he suggested to check the connection of the ribbon cable from the Left I/O
board to the logic board. He was right. The connector on the Logic board was warped and didn't connect properly. I removed it and straighten it up, re-connected it and BINGO, my Macbook Pro is working again. I switched again the Left I/O board just to make sure that the old one was bad and I finally realized that it was the case. The replacement of the I/O board was needed. Thank you all for your help and God Bless.