Computer Won't start up, the fans and fan lights kick on but the light on the power button remains off, I can easily turn off the computer manually.

SOURCE: computer wont start

I ran into the same problem with my Armada E500. In my case, it was a faulty RAM module. What I would suggest is start by removing the battery, and the charger. Then continue by removing the plastic section above your keyboard (there is a single screw holding it in place on the rear end of the laptop. This plastic covers the right-hand hindge) from there, there are four plastic tabs that you slide down to remove the keyboard. This will give you clear access to the ram. Remove the module(s) and, using a soft eraser, gently clean the contacts. If your laptop has two sticks of ram, I would also recommend putting them in opposite ram slots. After that, replace the keyboard and plastic bezzel, reconnect the battery and charger, and try to boot it up again

SOURCE: HP computer doesn't turn on

Your power supply is bad--you will need to replace. I suggest looking at tigerdiect for a replacement.

SOURCE: Fan is running, power button with blue light is off, cpu won't boot up

Your cpu might have died. As the computer is starting tap F8 and choose last known good configuration to see if you can get it started.

SOURCE: Can't turn my lappy on

Damaged Bootstrap You need to take it for repair

SOURCE: Optoma 719, can't get lamp and fan to turn on.

There is a stuffed 10v 3300uf capacitor on the power board. You need to replace it.
Bellow you can check in the picture where the capacitor is located.

Notice that in this picture I have already took the bad capacitor out and replaced with two small cords to reach the bottom and test the new capacitor.
To reach this place is not fast, several layers of plastic and metal must be removed, but is not a hard task to take the capacitor out and replace it for another.
It works just great! Now it is back on track with awesome image.