As this is not the forgotten password issue but a corrupt profile your recourse may be to try the XP REPAIR INSTALL (see google.)
Since both machines do this, is this something they have in common like a printer, network, torrent use, cracks, pirated software, that recent windows update noted at the top of the forum, some USB device you can unplug?
I can't log on 2 my computer running windows xp pro, I type in my admin password it acts as if it is loading my settings then it logs off. Can some one help? I've tried safe mode still the same thing happens.