[QUOTE=ashfaq;2597225]But when I right click my computer
Installed memory(RAM):5GB (3GB usable)
does it means that the pc uses only 3GB[/QUOTE]
Without a service tag no. from your computer we have no idea what is in your system and what expansion options it has. So we need a service tag no. And since you didn’t mention what O/S your using my guess it that it is 32bit O/S but until we get a service tag no. it be hard to know what your system is and isn’t???