trebor11584

hi guys, hope someone could help me out with my problem here is the scenario...

i have 2 40gig seagate hard drive, i made a partition on the other 40gig which makes it 20/18 (we all know that hard drives does not really extents to its full capacity), now i use the 18gig partition as my back-ups for my important files, the 20gig is for the operating system. the other hard drive which is the 40gig i didn't partition it, i use it to save my mp3's only, well, it also contains 1 movie... now, here's the problem the first hard drive the 18gig partition contains approx. 15gig of files size which would result in approx. 3gig remaining disk space but when i check the disk space it shows an approx. 900MB of free space, i try to show all the hidden files but there is no hidden files on my partition, i try to scan for possible virus but it is clean. now, i recently format both partition meaning fresh installed OS, but before that i transfer all my files to the 2nd hard drive which is the 40gig... when im done installing i transferred all my files again from the 40gig to the 18gig when it was done i checked it and it shows the correct remaining disk space, but the problem is i lost 3gig of disk space from my 2nd drive which is the 40gig after i copied all my files back. i try to check again to see if the files stored there corresponds to the remaining space but it is not, my mp3's is approx. 20gig the disk should show 15 to 16gig approx. but it only shows exactly 13gig of free space now im wondering what is happening to my system? what happen to the lost disk space? i hope someone here could give a remedy for this...