No keyboard in XP SP2 Setup Please Help???

I am trying to do a clean install of XP SP2 and whilst I have keybaord function for the bios, once I get to the text setup of the XP install where you have to press Enter to continue or R for Recovery console, the keyboard will not respond??? However just before this stage when the promt for ASR and the F6 options appear, the keyboard does respond and enable me to to halt the installation.....

 

My Machine is a Dell Inspiration 5000, which only has usb ports and no ps/2 so I am thinking there is some form of driver problem, i would happily try a ps/2 keyboard except there are no ps/2 ports on this machine.... is there a ps/2 card which I could plug into my mobo somewhere to get ps/2 ports??? I appreciate u can get an adapter which will convert a ps/2 to usb, but I don;t see the point, beacuse surely as far as the system is concerned the keyboard will still be seen as a USB one....?

 

Any help greatly appreciated??????