That is most likely an ancient or unsafe PSU (especially for a modern day system). Many people will come to this thread saying "yeah it's fine a 750Ti is low power" but no - you need to replace it. Very old design, from like 2002 about, and horrible capacitors, which literally were described on badcaps as "squishy" and "without a cover". http://www.badcaps.net/forum/showthread.php?t=38558