The XPS M1730 certainly does have a 64bit CPU. They sell with Intel Core 2 Duos, which are all 64-bit. Did you switch out the CPU? If you don't want to switch to a 64-bit kernel, you can increase the allocated kernel virtual memory space as discusses here: http://us.download.nvidia.com/XFree8...kva_exhaustion
. Changing your kernel possibly could have changed the way it allocated memory if it was very close to exhaustion, and caused this problem.