Check the properties and look at the total size and the amount which is free. If the amount of space used doesnt correlate roughly to how much space the files should take up, then try reformatting the card.
Is this a microSD card for your phone? If so, check that the files were transfered to the "external storage (microSD)" as supposed to the onboard internal storage. Also, make sure that your device is compatible with that size card.
yea its a microsd for my phone,but i load the songs through my computer using a card reader,whereupon reaching the 40 songs mark(which's less than 150mb),the extra songs start to act strangely like as if its a "cd with scratches" or the songs fade away only after a few seconds.And this is very frustrating knowing the card is a 2gb size.