I have a toshiba satellite i just found out that my CPU is overheating, does anyone know why it might be doing that, the 2 fans n the side runs but the fan for the cpu runs for a few seconds, please help

Check the fan with the laptop open (IF IT IS OUT OF WARRANTY), and see if the CPU fan completely stops. If it does not, then go to your local PC store (compusa, bestbuy) and get some Thermal Compound. Take off the heatsink and wipe off the processor of any old thermal compound. Apply a THIN layer of the new compound and test it out. Thermal compound usually only costs a few dollars.