Because I can not edit my message above ,
Ok, I've found the solution to my question , but now a new one occurs :
When I select PC as my input ( the other choices are hdmi , game console , blu ray player etc. ) I can only select standard and dynamic modes ( no game mod ).
If I select other choices on the list , game mode can be activated.
I am confused here , everyone tells , writes that we should play pc games with game mode on , but If I select PC as my input , samsung 8500 tv does not allow me to do so .
So, what should I be doing ? PC mode without game mode , or just like RTINGS tells movie mode and activating game mode ( during their calibration ).
thanks a lot in advance