Sammydnh :
This might shed some light on the situation when i turn on my monitor it says There is no signal coming from your computer
also my grahics card is freaking out and going in and out of fast and slow speeds in the fan
ok that means ur motherboard is in a reset loop.
if its doing it with your old cpu then something is wrong or bad.
Did you check that u didn't knock any cables loose any other component u may have knocked loose? try reseting the cmos by unplugging the computer AND removing the small battery for 5 mins. then see if u can get the computer to power on.
Other then that ur original cpu not woking is bad sign.
when it comes to ur new cpu it is an am3 without knowing what ur old cpu or motherboard is I cant tell if it is compatable with ur system at all. if you have an am2+ socket it usully requires makeing sure ur bios is up to date to accept the am3 cpu
without knowing ur whole motherboard name or model # I cant tell what u may have done.(though with it I still might not know the solution)