Depending on how much RAM and GB's on your hard drive it's a little hard to give a suggestions.
Anyway Puppy Linux isn't a larger distro like, Ubuntu, Debian, or Fedora which is larger.
You said:"downloaded xubuntu 12.10 and it won't load"
I'm not the expert but it could be hardware failure and the only way I know to test that is to run Memtest86.
Aside from that maybe the ISO image of Xubuntu was corrupt....did you check the integrity of the file with cksum? If not here's How To: