computer unstable

hello everyone.my first post

when playing battle field 2 online.......my ping jumps up and down alot..i use cable........this problem has just started since cleaning my computer...its affecting my game play.....like the game has the hiccups

ive been monitoring my voltages using asus probe.......
and they have been pretty choppy

including my cpu fan...which is a adjustible speed thermalquake model

i lowered my computer fan speed to half way.......and now all of my voltages are pretty stable again......if i run it full speed they get choppy

any suggestions? im guessing my power supply maybe?........