michael vorberg wrote:whats the difference in the machines? maybe there are issues with the graphics driver?
Well difference is both has different processor specs are mentioned below tired changing the graphics drives and card too it did not work for me but installed Win7 with sp1 it worked for Z230
HP Z230 Tower Workstation 1 x Intel Xeon CPU E3-1230 v3 @ 3.30GHz NVIDIA Quadro 600
HP Z400 Tower Workstation 1 x Intel Xeon CPU W3520 @ 2.67GHz NVIDIA Quadro FX 580