RAM Upgradation

it sounds really low as a desktop ram...anyway in amny cases is better upgrade ram when you buy anew pc/laptop because in this way performances should result much better!!I think you should read some technical documentation about the laptop in this way you cna see if you can use the same ram...

Unlikely. Check the User Manual for your laptop to see what type of memory it uses; open the memory slot (usually a separate little door on the underside of the laptop) to see if (a) there is a spare slot and (b) the size of the chip installed. You will probably find that the spare 2Gb in your PC is the wrong size. Now, knowing the type and size of the memory you need for the laptop and whether there is a spare slot, go to the store (or go online) and find the memory chip you require for your laptop. Memory is not that expensive.

Desktop RAM is usually larger than laptop RAM. You probably won't be able to use the same RAM for your laptop. They should have stickers on them that show how many pins they have. If the numbers from the desktop and the laptop match, you can use it.