Start Outlook Express and then Tools > Message Rules > Mail

If you are adding a rule click New.

If there are no existing mail filtering rules the New Mail Rule window automatically appears.

In Section 1 tick Where the Subject line contains specific words.

In Section 2 tick Move it to a specified folder (top of list) and Stop processing more rules (bottom of list).

In Section3 click contains specific words.

Type ??Spam?? and click Add then OK.

In Section 3 click specified.

Either select an existing folder or select Local Folders then click New Folder.

Enter a name - Spam in this example.

In Section 4 enter a name for the rule - ??Spam?? in this example.

If you have existing rules move the new ??Spam?? rule up or down the list as desired. Positioning at the top may cause false positives (real mail mislabelled as spam aka ham) to end up in the Spam folder. Positioning at the bottom may cause more true positives (spam labelled as spam) to end up with real mail. Note that the rules process in order from top to bottom.

If you routinely receive e-mail such as newsletters that are labelled with ??Spam?? you can create a rule to process it before the ??Spam?? rule.

Once created move the Newsletter rule to the top of the rule list so it processes e-mail first.