There's absolutely nothing you can do to stop spam e-mails arriving on the server of your e-mail provider. However, you can use software, such as Mailwasher, which lets you screen mail before it's downloaded from the server to your PC.
An alternative approach to spam is to use lots of different e-mail addresses. For example, I occasionally provide an e-mail address for a AB questioner to contact me directly. I nearly always create a separate e-mail account just for that questioner.
Please see my post here for further information on both of these ways of coping with spam:
http://www.theanswerbank.co.uk/Technology/Ques tion345829.html
Chris