Anyone who is using the DX58SO with USB problems at boot stage:
I had the problem too.
The problem was [solved] after installing BIOS 3044 dated 2008.
And if this older BIOS relates to another problem, try the next higher version but the latest BIOS version can have the weird USB problems.
My problem is with a DP55WB motherboard. There are only 2 updates for the Bios. This problem was supposed to be fixed in the second to last update (0142.2009.0909.2101). I installed the latest update(0165.2009.1110.1916). That fixed the lack of the single beep during post, but not the USB keyboard and mouse problem. Isn't the latest update supposed to be all inclusive? Since then I bought a new Microsoft USB keyboard and mouse. Still have the same problem. Now I have to reset BOTH cables to get either to work. This is definitely a bios problem. Most machines flash all 3 keyboard LEDs during POST. This one does not.