The second hard drive on my PC (running Windows Vista Home Premium)shows up as having 160 Gb used space when I right click on the drive letter and select "Properties". But if I then tally up the properties for each individual folder the space used only adds up to 125 Gb. How is this additional 35 Gb space accounted for? The recycle bin only holds 225 Mb of files, and all temporary files are held on the primary disc drive. Could this additional 35 Gb space be freed up by optimising the disc, or defragmenting it? IS there a way of optimising the disc?