Question about Toshiba Satellite M45 Locking Up

  I have a Toshiba Satellite M45-S331 which has developed a problem with
locking up.  Sometimes when i shut it down it gets stucking on the
shutting down Windows screen but many times what happens is when I
shut it down (and it does shut down) or close the lid where it goes
into hibernate as soon as I open up the computer and try to turn it on
it won't turn on.  I have even unplugged it as well as removed the
battery for a minute and it still wont' start.  Often it takes
removing the battery and pulling the power cord for over 15 mins or
so. Then it works fine.  
I thought it was a virus or something wrong with Windows so I did a
complete wipe of the hard drive and reinstall and it is Windows XP
Home Edition but it still has this problem.