|The total space used by the files does not equal the sum of all the file sizes. The hard drive is divided into clusters of a certain size. Your drive is probably partitioned NTFS and your cluster size would be 4 K. Each file will use a certain number of clusters but because it's unlikely the file size will be an exact multiple of 4 there will be space left over at the end of the last cluster. For example. If you have a 15 K file it will use 4 clusters. Three of those will be full but the last willl have 1 K of unused space. That space is owned by the file and can't be used by another one. So that 15 K file takes up 16 K of space. That leftover 1 K is sometimes called 'slack space'.|
That said, I doubt you have 75 gig of slack space on the drive.
Because a KB has 1024 bytes instead of 1000, the KB on your 160 gig drive will only show as about 149 gig. That might be part of the problem too. It depends on how you're viewing the hard drive size.
Another thing, are you sure it's showing the 160 (or 149) figure as the total size? Older bios' could only see about 127 (120) gig. If yours is one of those you may have formatted the drive and installed the OS without realizing all the space wasn't being used.
Some files are hidden and may not show when you scanned your drive. There's also a swap file the OS uses as kind of a ram extension. It's a hidden file that varies in size.
Anyway, those are some of the things that might be going on with your lost space. I don't know if that can account for all of it but certainly that's part of it.
Real men don't use AntiVirus; they just reformat