computer crash with rendering model need help

like the titel say my computer start to crash (sometimes i am able to render 1 time but when i do this a second time without restarting my computer it crash ) and sometimes this happens also the first time.
this is the type of computer i have

geforce GT 640

other information on computer

if you can help me but need my file to check out if there is another problem let me know then i send over the file in a message