I have a HP dc5800 which had an e2200 processor, I upgraded and bought an e6600 which has the VT-x option. I upgraded the BIOS so I could use the new processor. The PC seems to be working ok, I did not have an OS before so I am installing fresh. I installed the VMware ESXi and it does not detect VT is available, I do have it enabled in the BIOS. I run the vm.iso from VMware and it only detects CPU 0 is not VT capable, and CPU 1 has VT enable and working. When I try and install Windows (2008 or 7) from CD it give me blue screen of death before it ever gets to a menu. If I go into the BIOS and disable the multicore it will boot Windows fine, but the core that is left is the one that VT is not available on. Disabling the VT-x on the process does not do anything for the Windows booting. Any suggestions?