Over the years I did move the stand-off screws but didn't need to make new holes, plenty of holes were already there. I changed the power supply many times but

Over the years I did move the stand-off screws but didn't need to make new holes, plenty of holes were already there. I changed the power supply many times but it always fit, I think it's standard... Fans are on the mother board, there are no fan mounts directly on the case?