Hi vikram883 and welcome.

You cannot change these values in Windows 7 or in Vista.  Microsoft have decided that Windows can manage these parameters better than users can and so there are no user controls.

On most PCs these days, dedicated video memory is a physical RAM chip that is part of the graphics chipset and is impossible to change.  Windows adds shared memory to this from available RAM, up to the maximum of 1755MB automatically when the running applications (like games) require more memory.

A few computers may allow you to set a maximum for this shared memory in the BIOS but probably all OEM Manufacturers do not allow such changes in the BIOS.

The only thing you can do now as a user is to make sure you always have sufficient free RAM by maxing out the RAM.

It has been some years now since you could change these values.  Microsoft attributed a very significant number of computer crashes to users setting inappropriate values and so removed the facility.

mithcd wrote:

 

Thanks for that but I quite confused here as Microsoft still have a guide for this.

 

http://windows.microsoft.com/en-us/windows-vista/Change-the-size-of-virtual-memory

Unfortunately you seem to be confused permanently!  This guide is for something completely different.

Your link is to how to change VIRTUAL MEMORY - this has nothing at all  to do with VIDEO MEMORY.

Do you know anything about computers?