tried to overclock my gpu and cpu

hy guys,

recently tried to overclock my GPU gt9500 1 gb and
cpu intel E7500 2.93 ghz.

i overclocked my gpu by approx 10% and it showed improvement in framerates of RE5, GTA4 etc. and every thing seemed stable. didnt measure the temp that time but at default setting it shows around 50 C when i am playing a game.

after that i overclocked my cpu by 5% first it was stable then by 10% it was not stable then. at default it shows temp of 31 C and after 5% overclokin goes upto 50 C when playing a game like RE5. ws not able to measure temp at 10% overclok as it started showing instability just when i started the window so i closed it immidiatly.

so i turned everything back to defult not tried anything again.

plz suggest how ovrclokin wll affect my pc as i am afraid i might damage it.

thanks guys