There are DDR1, DDR2 and DDR3 RAMs. But I don't know how to identify them. So can you say me how to identify them.?
You can identify by the speeds (MHz) or the memory type (PC3200 or PC3-10600). You can even use the tool from this link: http://www.memorystock.com/memscanner/SysInfo.exe
It helps in identifying the memory information required to know. You should be able to make it out based on the model information.