I know that TAILS uses the Tor network for web browsing. Also it comes with encryption tools and things. I think you can also wipe your file system with some type of secure system cleaner but I'm not sure about that. Basically, the Tor network is the real anonymous thing. I've never used Whonix so I'm not sure about that one but it's probably similar.
TAILS should work on older PCs. I believe it uses the i386 architecture. I'm not sure about Whonix again.
entium M's?
