Hi Audrey,
Here's the link :
http://www.firetrust.com/en/products/mailwasher-pro/download

I suggest you go for the Mailwasher Pro (Not the 2011 version) on that page. I'm using a paid version - not sure if the version I've quoted is free, now that there is a later version (2011)

Mailwasher is not actually a 'Protection' program as such, it just filters out the Spam and marks it as such, before you actually download your emails to your PC.

Basically, it looks at the emails in your ISP's 'In Box' and presents their details on your PC screen. The actual emails are NOT downloaded until you have examined the content. Typical Spam emails are displayed in a different colour to 'genuine' emails and you also have the option to mark any of the entries as Spam or Friend should you wish to do so.
The program will gradually build a 'Blacklist' and 'Friend List' database, against which all your emails are compared.

When you are happy with the content displayed, you then click on a 'Process Mail' Icon and the 'genuine' emails are downloaded to your email client's 'In Box' and the Spam emails will be deleted from your ISP's 'In Box' - not download to your PC.

The program is only applicable if you are using an email client on your PC such as Outlook, Outlook Express, Windows Live Mail etc......
If you use Web based email then it's pointless installing it, since your email is not actually downloaded to your PC.

However, looking at your email address (BT) I would expect that you are using an email client program ????