New surge protector! Definitely. They can wear out or become faulty, and it just can't hurt!

Have you tried doing a clean install of the OS? Does it boot from the Installer CD?

As it is still under warantee, I'd go back and demand a new one - with a new warantee start-date, of course. Don't tell them you think your electrical supply might be the problem. Sounds like bad luck more than anything.