thank you guys for your advices...
any way I have returned the HDD and the store replaced it saying they made a mistake.

@ shanawazt - if your read my thread fully, I am asking what if the shopkeeper refuses to replace the item. dont you think the normal human being reaction/approach is to read the thread fully before giving a comment?

@ labeladas - the shopkeeper said all his HDD are 1Tb size, hes just not sure how the 160Gb got in there, funny huh?

@ aafi - i guess they did, wish it woudnt happen so often

@ rainjohan - lesson learned

@ niceguy00701 - thanks for your thoughts

@ tented - thanks you have the best advice, can you tell me the other places i could buy pc parts ?