help

[cfm lewis cfm]

hey i dont really nw where to put this buh my friends laptop keeps overheating and when i lookd inside the heat sink was black like burnt black.

the cpu still works ok other than overheating and being slow buh does any 1 knw what did this ????

also his bat died i while ago and hes just left the cable in when hes on it buh i dont think that could burn the heatsink :S

does any1 knw what i should do cus i dont what to find a new 1 if its guna happen again