hi and welcome to daniweb.
not a lot of info ,but i will add a few things anyway ,when running ,make sure it sits on a hard surface ,try cleaning the fan and heatsinc of dust ,or it could be more serisous ,like a bad video chip overheating ,and that will require more work than can be done on a help forum ,good luck
I've had this happen with one of my Dell laptops. It required a motherboard replacement on one occasion, and a disc drive replacement on another. If cleaning the vents and removing the dust from the motherboard doesn't deal with the situation, then more serious repairs are indicated.
hi , what is the operating temperature ? ambient room temp. Summertime ? no a/c ?
Most laptops are rated to operate up to 35 degrees C , less than body temp - does not take much elevated ambient temp to induce heat stress symtoms
Excessive ambient heat of ingested air used for cooling the cpu and chipset etc may or may not be a major factor - is why I ask