I use the Dell R44838.EXE file from Dell on my Dimension 8250 system. I used this software over the last 2 years with no problems and full functionality of the USB 8-Hotkey keyboard that also has a volume control on the upper right corner of the keyboard.
Search Dell for that file. I use that driver package on an 8250 system running Windows XP Professional. I don't know what results you will have running those drivers on a non-Windows XP system.