It's hard to disagree with the main reasons why clearing out old video and picture files, in particular unimportant ones saved while browsing, can offer improvements in the behaviour and performance of your computer system. The overall performance of your computer, particularly while reading out files from storage can be a function of how many and how large the files are on the hard drive. This happens because with more stored files, the FAT (file allocation) tables grow and the system has to do more work whenever it is asked to retrieve a file. Another key point is that files become fragmented (broken up into smaller pieces) and this increases when there are more files on the drive. Data security is also a factor, when you have a large number of your personal data files, there is always a chance that somebody accessing your computer will find them. Regularly cleaning out your hard drives with PC Scan software will make resources available again which can be put to better use.