I wonder if the failure here is a similar problem with the DLLs.
I've had trouble again just last month with ISE 14.5 on Win7 where I can't get anything to load.
I've encountered these same problems in the past before I downgraded from Win8 to Win7 (probably one of the reasons I downgraded). I've never had anything but trouble when installing ISE. However, Vivado only works with 7 series devices and upwards, so no Spartan 3 or Spartan 6 FPGAs! But all is not lost, here is how you can get ISE (64-bit) working on Windows 8. Xilinx ISE does not officially support Windows 8 and it probably never will as Xilinx are focused on their new suite - Vivado.
