Several scenarios:
If you have one (1) e-mail account through your ISP. I have 5, and only 1 account gets spam so I just put the other 4 account's e-mail address, in the following filter, and virtually all Spam is dumped in the folder of my choice. You simply need to create a 'white list'. Outlook Express gives you all the tools necessary to block Spam this way. You simply set up a Message Rule:
With Outlook Express open click the Tools menu; Message Rules; Mail; Click the New button; Under the number (1) 'Conditions' window, tick the box next to, 'Where the To or CC line contains people'; In the number (2) Actions window, tick the box next to, 'Move it to the specfied folder'; In box number (3) 'Rules description' click on the blue 'contains people' entry; Enter your first Approved Sender for example, goodguy@someisp.com and click the Add button; In the lower right New Mail Rule box now click the Options button; choose the option, 'Message does not contain the following people'; Click the OK button; Click the next OK button; Click the blue 'specified folder entry and then use the wizard to choose the folder you want to send unapproved messages to like, 'Deleted Items' (or a folder called Spam you've created prior to starting to set up this rule) (please see adding folders or sub-folders in the Outlook Express Help files); Click the Add button; Enter the next approved sender or, you can go back in this same area later by entering the New Mail Rule #1 (by clicking on the filter name), or whatever you named the rule, and clicking any blue approved sender again and then entering the next approved sender and clicking the OK button when you're done.
You enter all the approved senders you require to complete the whit list, and (after closing then restarting Outlook Express when receiving messages only those approved senders you designate to the filter will go in your Inbox. All others will go in the folder you designate. Note that if you use Deleted Items to send the non-approved senders to, in the Outlook Express Options area (Tools menu; Options; Maintenance tab) the checkbox should be cleared next to, "Empty messages from the Deleted Items folder on exit."
Emachines, Celeron 600, 256 Mb RAM, 30 Gb HDD, ADSL.