How many emails do you have in your inbox?
Is it just this one email you can not delete?
Option 1
One way is to create a NEW folder inside Outlook Express, name it DELETE ME.
Move the email you want to delete into this folder.
Then, go to "Tools>Options>Maintenance tab>Store Folder" option.
Press CONTROL + C (Copies the address to your Store folder)
Cancel out of these windows and close OE. (Outlook express)
Go to your RUN command from your start menu.
Paste the address you copied earlier and then press enter.
Now let's backup your files now:
Press CONTROL + A to select all the files.
Press CONTROL + C to copy all the files.
Leave this Folder open for now.
Open your My Documents folder.
Create a new folder in your My Documents and name it "Email BACKUP"
Open the "email backup" folder.
Press CONTROL + V
Close the "email backup" folder after it finished copying the files over.
Go back to the store folder, which should still be open.
Find and then delete the delete me.dbl file.
Restart Outlook Express.
Option 2
If you can not move the email in question
You can then leave it in the inbox, and move all the other email into another folder.
Then, go to "Tools>Options>Maintenance tab>Store Folder" option.
Press CONTROL + C (Copies the address to your Store folder)
Cancel out of these windows and close OE. (Outlook express)
Go to your RUN command from your start menu.
Paste the address you copied earlier and then press enter.
Let's backup your files first:
Press CONTROL + A to select all the files.
Press CONTROL + C to copy all the files.
Leave this Folder open for now.
Open My Documents.
Create a new folder in your My Documents and name it "Email BACKUP"
Open the "email backup" folder.
Press CONTROL + V
Close the "email backup" folder after it finished copying the files over.
Go back to the store folder, which should still be open.
Find and then delete the inbox.dbl file.
OE will create a new inbox.dbl file for you when you start it back up.
Hope this helps. I've done this once and was a while back.