Just a suggestion - check which USB ports you are plugged into. Do not use the USB 3.0 ports. Plug them in direcly to the read ports (do not us a hub).
I have only used USB wireless with my DX58SO2 and have never had a problem - Logitech wireless via a unifying receiver.
But - I am running Win 7 64 ....
Good luck - hope this helps.
Thanks R ! A bit delayed but thought I'd just update the thread. Turns out that the old Keyboard/Mouse were PS2 and as such the drivers remained in operation - without of course any PS2 ports on the machine (not PnP of course) and ignoring the new USB ports ..... . Finally resolved by installing a fresh copy and then altering the old registry to exclude the PS2 items and include the USB drivers etc. it was then able to boot and locate the relevant drivers with PnP. The clues were provided by assistance from the nLite forum, too whom I owe many thanks! In case its of help to others all the gory details here Change of M/B due to fault under Win2k3 - MSFN Forum - Page 2