BIOS problem ( I think)

[superdupermido]

i measured the voltages from power cables , giving 5 and 12 volts, in addition the fan is working , so not a power problem I think,

Also I think it's not a video card problem as the video card has nothing to do with drive not opening.

Other symptoms I forgot to mention : the HD LED is not flashing, I hear no start-up beats

[Allan]

Okay, back to the power supply or motherboard in my opinion. CPU is also a possibility. It's just very hard to diagnose this type of problem on a forum, sorry.

[superdupermido]

that's the first time since 2006 that computerhope lets me down

[Geek-9pm]

Not over until the Geek speaks.  

Some details missing.
Make and model of the motherboard.
What kind of Graphics adapter? Make ad model and type.
Some AGP cards cards  stop the motherboard.
Do the keyboard lights flash? How many times?
Normally most DVD drives will let you open the drive is power is applied.

With power off, you can try thins:
Remove cables from board. Remove power for all drives.
(Bad cables and bad drives stop everything.)
Remove RAN.
Remove all USB devices. All devices.
With case open, power up and observe fans.  All fans should come on.
Thee ought to  be a beep, even three  beeps. (No RAM.)

Still not sign of life? If not, the motherboard is now the prime suspect.

[patio]

that's the first time since 2006 that computerhope lets me down

It's either the Power supply...or the HDD connection itself since you stated 2 HDD's did the same thing.