I've tried some free editing programs on my win7 64bit. It's true how the memory is a huge issue. Be careful when choosing a free program to try. I literally knew hardly anything about editing, even though I work in cinematography, but the easiest, bare bones, get your stuff into sequences, program I really liked was called Videopad Editor. It came with a bunch of other side programs for converting file types, which I never used.
With this software, I found it much easier to use the storyboard view rather than timeline view to create my sequences. Just don't delete your backup files.