Monitor Display Problem due to fan loud sound?

My colleague has a computer which system board big tech motherboard; graphics card NVidia, fx55 processor. when he turn his computer on, it will stay on for the most about 2 and half hours or at the least 2 minutes before the display on monitor distorts, lock up computer and restarts. Sometimes it would do this few times in a row before finally there's no display at all but can hear the comp running its programs as normal also PSU fan running , he confirm to listening music .what is the problem?. Here that processor fan makes load sound. Could this small fan cause it to distort display and lock up comp?
