I am having a similar problem with my 2 year old G35-650. I get the same lines and eventually a blank screen. I was able to boot into safe mode and disabled the GE force video driver and now am able to boot up with a generic windows...
Computer wont boot up with the nvidia driver in place. Can boot up with safe mode and in xga mode after driver is removed. There was a screen that occasionally popped up for 1 sec when attempting to boot up with the nvidia driver in...