LR,
There has been some discussion on this recently - both keef and IO540 (among others) have posted some good advice. Rather than repeat it, may I suggest that you "trawl the archives" to find it.
If your private email address has been "harvested" - either from a site you have visited, or by a friend's system being compromised - there is not a lot you can do, short of creating a new address.
However, my experience is that if you put up with the spam (and NEVER respond), it may abate after a while, usually coincident with that particular spammer being shut down.
But do create at least one more "junk" email address that is used for registering on websites.
SD