I built an ECS A790GXM-AD3, stuck 4 gigs of DDR3 1333 in it, an AMD X545, some cheaper ATI card (I don't even remember what number it is), and a 500 gig HDD.
Anyway - the machine POSTs fine, will boot XP and vista fine - but only under certain circumstances!
Launching either installer for XP or Vista (haven't gotten around to trying a linux live CD yet..) results in an error screen for XP and Vista just endlessly showing the progress bar.
I then attempted sticking a different HDD that already had XP on the drive - booted right up no problems.
I proceeded to install Vista (the requested OS) on the 500 gig drive, but on my personal computer - installed and booted up fine. Following this I reinstalled the drive and the machine booted up vista fine - however soon as it restarted for updates - the error occurred again.
Sure I might be able to get the machine running for now - by disallowing any kind of update on the machine, but that is not a permanent solution.
I've elminated the possibility of virtually any bad hardware so I'm guessing it's a BIOS setting - however I've yet to find anything on the ECS website describing such an issue.