BIOS stoping at INT-19 (Post card error msg)

[TwinDrake]

Hi

I got a problem with a PC who won't even start, so i installed a post card and the message it gave me was "00 : Copying of code to specific area done. Going to give control to INT-19 boot loader". The fans and CD-drive all seems to work when I power the PC on but nothing shows on screen and the led for HD activity doesn't show anything (might be just the connexion to the led).

I got 2 of these PC, 1 working the other not so i went and remove, 1 by 1, all the pieces of the not working one and put them in the working 1 to see wich one was defect but all (CPU, HD, RAM, Power Suply) just work fine when they are in the working PC.
We did change the motherboard once with no result, so what are the odds of having the same problem on 2 different motherboard ?

So I was wondering if any of you got the same problem, or if you have any idea on what the next logical step should be. If some part of the problem doesn't seem clear juste ask, I'll gladly answer.

Thx