i just have a general question about hard drive space. i recently used the emachines system recovery to reinstall a new OS but i also opted to backup my entire old OS to save some important files. my original OS was about 20 GB and when i reinstalled my new one, the C drive now was using 40 GB(pretty logical right?) after i got my needed data, i deleted the backup folder that contained all the files from the old OS, however my C drive still reports me using around 33 GB. so i was wondering what's the mismatch all about? where are these "secret" files that are taking up my HD space?

edit: i searched around and i noticed people have been saying how you lose disk space after a reformat. is there anyway to recover that disk space?

Check to see what junk the recovery disks install along side the os. Also try file cleaners and if your picky about what goes, do a search on your harddrive and opt to only see things that are above xmb in size.

Backing up your old OS is not the same thing as backing up the entire contents of C. What did you back up? The OS itself takes up less than about 3gb, even with all the Microsoft Updates installed. Depending on the method used, the backup may have been compressed so that it takes up a lot less disk space. "my original OS was about 20 GB and when i reinstalled my new one, the C drive now was using 40 GB(pretty logical right?)" That doesn't make sense, unless you un-installed a lot of the original software in the emachines software installation. The old contents of C would likely take up a lot more disk space than the software installed by running a full emachines recovery procedure because you had added software and files. "i deleted the backup folder that contained all the files from the old OS" Again, what was originally on C was not just the OS. You never delete what you can un-install - in that case, deleting does not remove as much as un-installing it does. Partitioning and formatting always take up hard drive space that can't be used for data - there's nothing you can do about that - that situation and the amount of disk space taken up by that does not change when you "re-format" the hard drive the same way as it was originally. Hard drive manufacturers have always used a bogus decimal size for hard drives. Operating systems and probably your mboard bios use the binary size of the hard drive (or partition on it), which is always less than the manufacturer's size - the total number of sectors on the drive is the same. If you confuse the two methods of specifying the size, you may think Windows is using more space for partitioning and formatting than it actually is. E.g. a hard drive manufacturer's 80gb drive ends up as being about 74gb in binary size, total, after it has been partitioned and formatted. Brand name system's original software installations always make two partitions on the original hard drive - the second one is smaller and contains all the data needed to restore the original contents of C - in the case of that example 80gb hard drive, the size of C would be a lot less than 74gb. The second partition is usually nearly full, having just enough, or a little more, free space in it such that you don't get the low disk space warning about it all the time

hmm i guess it didn't back up the "OS" just my old files from C:\. so that means my computer does not recognize any installed programs from the previous OS. during recovery it also mentioned that it would only backup my files and that i would have to reinstall all my old programs. so it would have been safe to just delete the files right?

NOTE: i just used a program called directory size that lists how much space each file takes up on the HD and how much it is all together. according to the program, it says my C drive is only using about 18 GB in files when the properties of my drive lists 29.3 GB used space! (it's different from my original post because i cleaned up a few things)

Did you empty the recycle bin?