well to start im fairly new with apple, i bought an ibook g4 from a friend that turned me on to apple and did my reseach aswell as some upgrade which consist of a 1 gb memery ram Superdrive and 100 gb hard drive. installed leapard 10.5 then installed i life 08 everything was fine the machine ran great FOR A DAY.now all it does is load up as normal and then it goes to a blue screen loads back up as normal 10 seconds later it goes to blue screen and so on and so on.im getting really aggravated.in those ten seconds i went to disk utility then activity manager and seen one thing in red and it says login window not responding.im out of options PLEASE SOMEONE HELP!!!