I have just established Outlook on 4 PC's networked across a LAN.  Outlook & Outlook Express were working fine until I was curious about the workgroup function and wanted to check it out.  Although there was a warning that Outlook would need shutting down there was no mention of requiring the office disk to restart Outlook. 

Since my Dell is OEM I don't have the disk and now Outlook keeps trying to install the software for workgroup from the disk!  I have to cancel the install setup everytime I try and launch Outlook and get error msg:

"Cannot start Microsoft Outlook.  MAPI32.DLL is corrupt or the wrong
version.  This could have been caused by installing other messaging
software.  Please reinstall Outlook"

Currently Outlook can't be launched plus Outlook Express will now not open it's address book and although I can view incoming mail, I cannot reply to emails or file them. 

I'm not fussed about the workgroup option so how can I set Outlook back to "Internet Only" option??

Thanks