Same problem here, on a Phenom X6 based system with a 60GB vertex2 and Windows 7 x64. Memory is fine in Memtest86, fiddling with BIOS prefs and versions did not help. Whatever I do, the system will not move past POST if it is restarted from running previously in any way, even via the reset button on the case. Yet booting from power off works like a charm.
What kind of strange error is this?