Best way to stop spam
Hard to do own your own with your current email address if your email provider does not give you any tools to do so.
Best bet is to have 2 email address
One you use with your friends and another you use to fill out online forms with.
Places like your bank, credit card companies, etc.are safe to give out your main email, but most any other place that you type your email address in gets sold to spammers.
On the computer question;
Lots of small book size laptops out on the market, for a regular PC I know that Dell makes a small PC...It's bigger than a book though. My experience has been you pay for the small size and do not get the bang for the buck in performance so not something I have researched much.
Hope that helps,
Jeff