Windows 8 graphic card prob..pls help

[kanish]

i bought a win 8 desktop..inbuilt graphic memory is already present there .i installed many games. it was running slow .i bought a nvidia graphic card geforce 7600 256 mb and inserted it.before i dint disable it in device manager..after inserting it worked properly ..it showed it in dxdiag box total memory is 1017mb graphic card including the old inbuilt..but now also the game runs in the same speed no diffrence..i thought of installing the nvidia graphic when i tried to install it said - nvidia installer cannot continue this graphics driver is not compatibleto this verion of windows...'''''''..in device manager also only nvidia geforce i showing up not intel graphics..i tried of removing the graphic card and disabliling in the device manager..but when i remove the nvidia graphics card .system is turning on fan and lights are running..but no signal in monitor..now any has any idea of disabiling the internal graphic card without removing the nvidia card...because i need to overclock gpu..when i install msi afterburner..i cant change any values..tried other overclocking apps also..cant change..pls help..

 

[kemical]

Hi Kanish,
apologies no one answered your question did you still need any help? If you do can you post your system model and operating system thanks.