You need something like DamnSmallLinux, not Debian. Debian users about 800 MB of RAM with XFce, on a clean boot. It requires a minimum of 2 GB with a modern browser (one tab, 4+ GB with more tabs). DamnSmallLinux uses about 128 MB RAM on a clean boot, and with the Netfront browser about half a gig. Definitely better for such a laptop than any modern distro.