Toshiba A205-S4577 does not come up

Hello,
When I power on my laptop Toshiba A205-S4577 it brings up the initial screen "TOSHIBA Leading Innovation" and the lower bar with "Press F2 for System Utilities, or press F12 for Boot Menu".
After the lower bar fills about 80% blue of the sliding bar the PC stops and hungs and there is nothing else to do. Powering down and up again takes to the same point.
The hard drive is okey, I tested it in a friend's laptop.
It seems that after initial boot up, the bootstrap loader can't make its job.
Some ideas to help me please?
Thanks everyone.
Milton.