My Dad's account failed to load properly today. It booted to some sort of default account instead. I tried again and the same thing happened.

A message bubble appears saying it hasn't loaded correctly. None of his documents were visible in the Documents folder. It's clearly not even attempted to log in as his user. Not even his wallpaper appeared. It mentions a log file but gives no means for me to access it.

I have taken no action to fix this yet, I am hoping that there is a very simple way to rectify this. I don't want to have to recreate the user account (which will take ages due to user settings and so forth).

Can anyone shed some light on this? I'm not a vista user usually, so I'm not familiar with the means of fixing such things.