Default samsung tab restarting...

ok i got this tablet about a week ago and it had a cracked digitizer but everything still worked great.
i used it for a week with no issues.

today i received the new digitizer and i followed a video on youtube
i did exactly everything right.
now the tablet keeps restarting

it restarts about 10 times then it works... after about 1 hours it does it again?

any clues???