All you can do is just keep deleting them, and they'll eventually stop. The one thing you musn't do, is reply or unsubscribe, because then, your confirming your email addresss, and you'll get even more.
firefox doesnt help. I have firefox and in my work email account regularly get over 20 spam mails every day. I really dont know how to stop them - I just deleting them.
Hmmm, as Lonnie says, never reply to them. Best thing to do is just delete them. Dont click on any links whatever you do, otherwise viagra ones wont be the only ones your getting. Most are from other sites you have joined and they have sold your details on. Be careful which sites you register for. This one seems ok as i have never had any when i joined this, but i joined a dating one once and got absolutely loads off other dating sites which i had never been on...not that i remember anyway...
Just to add actually. If your ever signing up for something, always use your alternative email address as it could work in your favour. It wont get closed as you will always get crap sent to it, so its active.