CPU starts overheating and causes beep sound prolong

[Athinivas]

Hello,
This is Athi.....I have a Asus p5KPL-AM IN motherboard....It works for well for more than 5 months....now it starts overheating much....i checked my fan speeds and also removed all dusts inside it....but still the problem persist.....mainly when i open a gaming program it will raise upto 56 deg celsius suddenly...and there comes the prolonged beep sound(1 long)....can anyone help ??

 

[Raiddinn]

What are all the rest of the parts of your computer, including the case and PSU? How old are all those things?