hi this is Ashwin from New Delhi, India. Recently my computer went for repairs & my RAM got reduced from 512 to 384.I had 2 x 256 MB DDR. When I asked the computer guy about it, he said that my old RAM had got spoilt and its now showing only 128. IS IT POSSIBLE FOR A 256 MB RAM TO BECOME HALVED AND SHOW 128 MB RAM? Or has the computer guy taken my RAM and replaced with an old 128 MB DDR.

Usually this is a motherboard error or a socket error. But sounds like a stoopid tech error.
Motherboards do sometimes have failures that cause this. Often not fixable. Look very closely at your memory module. Remove and reseat the memory. Try another borrowed memory module to see if the problem is in the memory or the board.
Download and run MemTest86, a great, free memory checker, so see what reports you get. Run it for four hours or more.

There is a freeware program called SIW (System Information for Windows) that you can download here. If you go down to the hardware section there is a subsection for memory which will show you the total memory, and then breaks down to the individual modules.

This will display the following.
Device Locator (slot 1 or2)
Capacity
Memory Type
Speed
Data Width
Form Factor
Total Width