test hard drive with mhdd (if sata, must be set to "as ide" in bios instead of "ahci")
test memory with Memtest (and shake memory dimms while testing) the test should not stop as you shake the dimms. if it stops, use contact cleaner (DeoxIT)
install windows on the workstation (to be sure the machine is working fine)
reinstall PfSense with default settings
finally, give us an update.
by the way, why are you moving to machine installed pfsense instead of Virtualisation setup?
zikmen