Based on your description I suspect the BIOS update caused the system not to be able to POST somehow.
I suggest you checking what BIOS version they used. Since the motherboard had an older BIOS version it is highly recommended to update it incrementally.
Try removing the CMOS battery and power for 20 minutes and then attempt a BIOS recovery.
Desktop Boards — Computer does not boot after changing BIOS settings
Desktop Boards — Instructions for Recovery BIOS Update
It is a good idea checking if you get the expected beeps when the memory is removed.