Stan, it helps us a lot if you tell us what OS (Operating System) you are running and what version of OE (Outlook Express).
There are several things you can try, but it depends on what OE you have. You can download Msoe.DLL file from online, but you need the proper one.
You could try searching your PC for this file (Msoe.DLL) and copying it into it's rightful place, C:\PROGRAM FILES\OUTLOOK EXPRESS
Another option...as a last resort, you can try SYSTEM RESTORE. (restore computers state to an earlier date)
Let us know OS and version of OE and lets see if we can help ya figure this out