Asus g73jh bsod when boot try again till it finally boots and works fine help

i have asus g73jh was given to me, installed 8gigs ram, had 2 gigs there already, installed new hdd 1tb in one slot only installed windows 7 o/s worked great 1st day or so then started getting bsod upon strtup, but, i keep trying to boot and after 2 to 3 tries i am up... works good .. what could be causing this isssue of data dump on bsod,,,, its getting to be a hassel just to boot the computer any advise would be appreciated... thx pippo