Dreslough
Your Outlook Express problems may be fixed thus:
Ensure that OE is closed
Navigate to a folder called 'folders.dbx'. This will be located in your identity folder in the OE folder. The location will depend on your OS.
Delete folders.dbx
Open Outlook Express.
Folders.dbx manages the inbox, outbox etc folders in OE. On occasion it becomes corrupted, causing,among others, the symptoms you describe.