Computer crash

I have two x64 Bit windows systems one with GTX285 and Tesla C1060 and another system with GTX295.
I am able to run my code on the system with the GTX285 and C1060 using two threads, each working with
a different GPU. However on the second system when i try to use both cards the computer crashes after a few
minutes (the code works fine on one of the GPUs). Looking at my application logs shows that the computer seems
to have crushed in the middle of the computation. The computation takes ~200ms and happens many times over and
over with different input.

Any idea why? how to debug it?