|Socket 478 P4s don't support NX. The oldest processors that will run Windows 8 are:|
Most LGA775 P4s and Celeron Ds
Most Dothan-cored Pentium Ms
All Athlon 64s
All K8-based Semprons
I believe the last version of Win8 that didn't require SSE2 and NX was the consumer preview.
Super PIII | Unlocked ES Tualatin @ 1.8GHz (150x12, 1.65v, 512K L2)
3GB PC2700 | 500GB | Radeon x1950Pro | Apollo Pro 266T | Win 7 Pro