Locate your OLE32.DLL file. The default folder for this file is
C:\Windows\System32. Click on Start | Run. In the "Open" box, type:
regsvr32 c:\windows\system32\ole32.dll
If necessary, replace "c:\windows\system32" with the actual path to the
ole32.dll file on your computer. You only have to run this command once (not
every time you start the computer).
Check the settings for the service you're using. (Your ISP will tell you
what they should be.) If you can send but not receive, perhaps you've got
the outgoing mail-server entered wrongly -- it's often not the same as the
incoming server.