newbee help

hello
i had this computer for 3 years, but for now every time i run a program or some time if i watch a long video on youtube, my fan run high making this loud sound that never shut off and it slow way down, i been thinking about adding Dual-Core Processors and 2 gb of Memory, will that help :confused this is what i have now
Manufacturer : Compaq Presario 061
Processor : AMD Athlon 64 3200+ @ 2200 MHz
Physical Memory : 1024 MB (2 x 512 DDR-SDRAM )
Video Card : Silicon Integrated Systems (SiS) SiS661FX/760/741/M661FX/M760/M741 GUI 2D/3D Accelerator
Hard Disk : WDC (200 GB)

thank you

 

First thing I would do is open the computer case and clean out the dust. Be sure clean dust out of heatsinks (on CPU, video card, etc.).