Advanced Dell Precision 690 USB Controller Problem

My dell precision 690 case was so old and USED that it literally started falling to pieces.

1) the case door wouldn't shut properly.

2)the power button switch snapped off.

3)all the HDD caddies had snapped due to overuse.

4)The DVD kept jamming

So I decided to buy a new case for my motherboard and internal hdd/peripherals.

My original system was a Dell precision 690 it had a MY171 with dual quad core processor x5355

The service tag was - 5WMGSJ 

The case I bought for a replacement was another Dell Precision 690 with a DT029 motherboard the service tag for this system was  <ADMIN NOTE: Service tag removed per privacy policy>

I have replaced the motherboards (as my one was dual quad core as opposed to dual, dual core) and managed after some tweaking to get everything going all that is except the USB controller which seems to work ok with USB keyboards and mice but not with USB keys or external devices (hdd/cameras/port replicators etc,)

I reset my bios to load the essential driver setup again it doesn't recognise the drivers.

in the BIOS my service tag now reads as 0000000.

I have tried going to device manager and deleting the drivers for USB's then restarting the system hoping that this would prompt it all to no avail, I also tried to find the drivers from Dell support for the  Precision 690 again without success.

Not even my ORICO PME-4U USB 3 card is working even although it worked before.

Does anyone know what I could do to get this working?

I have the original hard disk in with windows 7 X64 everything was working before perfectly which brings be to believe that A)

A) There must be something wrong with the USB controller in the new case

or

B) That the USB Controller in this case, is somewhat different from the other and needs a specific driver.

Any ideas?

Thank you

HH