Logitech Cordless MX Duo - Laptop Keyboard & Touchpad NOT WORKING

I bought the Logitech MX Duo cordless keyboard / mouse unit and installed the supplied software, itouch 2.15 and Mouseware 9.75

My Laptop is a Dell Inspiron 8000 running on W2000.

The Logitech unit works but now neither my Laptop keyboard or touchpad work any longer.  I cannot use my laptop alone, if I unplug the USB Logitech unit and restart, the Laptop keyboard and touchpad do not work.

I found a posting on this site with a similar problem on a different computer.  The fix posted by dean.forbes

suggest going to the path

HKEY_LOCAL_MACHINE/SYSTEM/CurrentControlSet/services/i8042prt/ and changing the start string from 4 to 1.

I am cautious about editing the windows registry and wanted to know if this fix has worked for anyone else or is there another approach to the problem.

When I contacted Dell support and tried normal rebooting sequences and safe mode attempts, it was suggested that a Windows re-install may be required.

Thanks.