Depending how old your Hard Drive is, it may be going bad and causing some hang
ups. Or the IDE or power cable to the hard drive may not be in all the way? You
may have bad ram or too little ram, the processor may be bad, and so on. It
could be many of things. So the clue is that it hangs up on XP and Ubuntu, so
starting to debug hardware may be the key.
When does the system freeze up? Is there a program that uses huge amounts of
ram. Like a java application like Frostwire.