How to Low the temperature of my CPU

Without knowing what processor you have it's hard to say if it's overheating or not, different processors have different operating temperatures, but it does seem to be running on the hot side.

First thing is to clean the system of dust, clean out the fans and open up the case to clean out the heatsink fan. Overtime dust build ups, reducing air flow and increasing temperatures. Beyond that would to buy a better heat sink or more case fans.

Its Intel Pentium D

Oh boy, P.D's like to cook, what model and just post the temps, a lot of people won't click on links.