Motherboard probs

hi,
My sister had an intel system which broke down about 4 months ago. Motherbard and cpu crashed somehow and the warranty was over by a few days. well bad luck. So to fix her pc i ordered another intel board which didnt work either so i went to amd as all my systems have and had amd cpus.
well my bad luck continued i ordered another 2 boards and cpus which didnt work either.
So yesterday i received the 4th order (asrock s939-dual-sata2 with a 3000+), i installed everything and thank god the pc went on but then it stopped at the screen where u can enter the bios. As this was the first system with a 939 i could check everything with my own pc what came out was that everything seemed to be ok but the motherboard which made me curios as it came as far as the allready named screen. Well i have already send it back but could anyone tell me if my sisters pc is doomed or a helping solution. The Problem is that i have never had problems with my own system which i build myself and the many other systems which i have built for friends.
i would appreciate any answer

Hmm, have you tried a different PSU, different RAM, etc?

yes checked everything that possibly exists