Fixed the problem. These XP machines DID have a mailto item in the registry. And, using Windows Explorer | Tools | Folder Options, locating the File Type of "URL:mailto" protocol, it WAS already pointing at Outlook. Clicking the "advanced" button, then clicking "edit", showed the following:

"C:\PROGRA~1\MICROS~2\Office\OUTLOOK.EXE"

Adding a parameter on the end fixed the problem. The new value looks like:

"C:\PROGRA~1\MICROS~2\Office\OUTLOOK.EXE" -c IPM.Note /m "%1"

>David:
>
>checking that now. found the users where getting a return code of 31, which is "SE_ERR_NOASSOC = 31". checking now...
>
>
>
>>Chris,
>>
>>Make sure that XP box has a mailto item in the registry. It should be right under HKEY_CLASSES_ROOT
>>
>>>The following code pops up an Outlook "new msg" window. This works fine on Win2k PCs. But no window is displayed on WinXP machines:
>>>
>>>

>>>ShellExecute(0, "", "mailto:" + lcEmailAddress + "?Subject=" + lcSubject + ;
>>>             "&body=" + lcMessageBody, "", "", 9)
>>>