server down again….

some my local linux server keeps freezing and i dont know what makes it do that. i will have to power it off and reboot it this is really starting to bug me because that server host my art blog and will soon host my art store. its running ubuntu server 9.10 or 10.4 one of those two and i cant seem to figure out what is causing it to freeze up i’m wondering if its not just over heating.  if any one may have a clue as to where if any i might find logs showing the crashes or errors