I've downloaded and am about to try mw9791enu.exe from Logitech to set my wheel button to double click. I noticed the following from the download WEB page.
Title: MouseWare Version: 9.79.1 build 25 Posted: 01/08/2004
SPECIAL INSTRUCTIONS FOR WINDOWS® XP
Logitech serial pointing devices in Windows XP:
Pointing devices connected to the serial port are no longer supported by Logitech MouseWare in Windows XP. If your device is a combination PS/2 and Serial mouse, we recommend using the PS/2 connection. If your device is serial only, you must use the operating system's native drivers.
Before I install mw9791enu.exe, since you apparently downloaded and successfully used mw9791enu.exe, I was wondering if "PS/2 and Serial" referred to the old "SerialPort" or to today's USB. Does your Dell Wireless Keyboard and Mouse use USB or PS2 base receiver?