...and you can't hide your IP address anyway. That's like trying to hide your home address -- you can physically remove the numbers from the post box or front door, but your home is still located at "123 Main St." and the mailman is still going to deliver your mail to your home regardless of whether he can see the numbers or not.
There is no way to "hide" your IP address. Also, downloading an ISO image from a website will NOT cause a flood of spam... that is, unless, you entered your email address on that website, say, to gain access to it or to sign up for a user account. Simply downloading a file from a website cannot generate spam to your email address -- your email address is in no way linked to your IP address, and it is impossible for downloading a file with a web browser to cause you to get spam. Those two events are about as unrelated as they get.
Get a spam filter for your email. The only other way to stop the spam is to fly over to Nigeria, Russia, China, Germany, or wherever the spam is originating from and kindly ask the spammer to stop sending it to you.