I noticed that to be exact, when my system hanged, ALL usb ports have no power. Eg, my mouse has no light, my thumb drive has no light. But everything else including my PS2 keyboard, my casing fans, my dvdrw drive and my processor fans are all working.
I do not think its a PSU problem as this will either cause instant blackout/shutdown, not just hang. I was told it might be a USB problem with my mobo or maybe something to do with the casing.
I will probably try to run the bare setup outside my casing to see if it works