try changing the vaule in this registry key...
HKEY_CLASSES_ROOT\mailto\shell\open\command
This is the default Mailto area. The Eudora program will more than likely be set. if you want to use outlook you will need to know the path to outlook.exe and paste is in the value for default...
remember when working in the registry, you always back up before amking changes... office 2003 installed. Yours will be different if you have a different version...
This is the vaule I have. "C:\PROGRA~1\MICROS~2\OFFICE11\OUTLOOK.EXE" -c IPM.Note /m "%1"
good luck