DX79TO, mouse and keyboard inoperable after waking from standby

Hello.  I purchased a custom built PC recently.  Here are my spec's:

Intel DX79TO motherboard, BIOS version 0460

Intel i7 3820 CPU

Intel 520 series 120GB SSD

Windows XP Home SP3 (windows updates all current)

Asus GeForce GTX 560 Ti

Logitech gaming mouse, model G700, USB 2.0, wired

Compaq keyboard, model KB-0133, PS/2 with USB 2.0 adapter, wired

In the BIOS, on the Power tab, "deep s4/s5" is set to disable.

For the keyboard and the mouse, in device manager, both are set as follows:

* disabled and unchecked: allow the computer to turn off this device to save power

* enabled and checked: allow this device to bring the computer out of standby

The PC will enter standby just fine.  When it wakes from standby, both the keyboard and mouse are inoperable.  I have to power down the PC in order to correct the problem (no choice, since neither input device works!).  After restart, everything is fine.

I didn't notice anything related to this issue in Windows Event Viewer.

My old Compaq PC (Pentium 4 on a micro-star ms-6577 motherboard) used the same keyboard and same mouse and Windows XP Home SP3 and EVGA GeForce 7600GT.  Standby works fine on it.

Any ideas?  Thanks!

UPDATE 4/7/12

In the above info, I indicated "when it wakes from standby".  You might wonder how it can wake from standby when the mouse and keyboard aren't working.  I confirmed that both the mouse and the keyboard will cause the PC to wake from standby.  However, once the PC is awake, neither the mouse nor the keyboard continue to work...after that initial keystroke or mouse gesture, neither device works again until the PC is powered down and restarted.