Thanks... I finally solved my problem by removing the space bar and cleaning the little object that was blocking the space bar from going down.
It is tricky... I pulled the space bar up starting from the top corners (top meaning closer to the screen) using my nails. I pulled up slowly, but firmly. The whole space bar came out with the two metal "hinges". I removed the little thing that was blocking the space bar and replaced the space bar key.
The key is held to the keyboard by two different "hinges". The top hinge (closer to the screen side has two 90 degree angles bends. The bottom one only one. Enter the "hooks" of the top hinge in their slots on the keyboard (behind each one of the "footings"). Do it one side first, and then,the other). Proceed to align the bottom hinge (one 90 degree angle) with the little whole in the metal bracket that holds the top hinge. Make sure that the plastic scissors-like base are aligned and the inner loop one is hooked to the corresponding latch.
Bring the space bar key vertically onto the keyboard,making sure that the bottom hinge tips are aligned with the little whole in the latch for the top hinge. Press firmly. You will hear the click. Make sure to press on each of three "footings".
Hope it helped.