If booting into safemode is ok,this maybe points to a driver issue.
First thing i would try;
Remove the keyboard (disconnect) does this boot ok ?
Remove any usb devices (disconnect) and try to boot the machine.
I strongly suggest if you can boot into safemode then run your anti's,a rebooting machine while trying to boot into windows can be the work of a Virus.
Try these tips and post back if no joy.