A system restore won't help at all as it will only change your own computer but won't have any impact on anything external to your system. It's like trying to change history - you can't.
The only you can stop it definitively is to change your email address, which is likely to be an impractical solution. The next best approach is to get a spam filter and as you mark the incoming emails as spam, it will 'learn' how to recognise spam. There is a danger that you will get false positives so you will need to look from time to time to see if it has caught any 'real' emails.
Sadly spam it's a fact of life, it's the equivalent of air pollution in our towns and cities.