Defragmentation should not delete data. It merely makes files contiguous (goggle it). When a file is fragmented the computer has to read the FAT (another job for google) to discover where the next fragment is. This involves disk head movement which slows down the disk. So having contiguous files makes head movement back to read the FAT unnecessary.
The program you used must also have a ‘disk cleanup’ element to it. I hope so anyway.
Defragmentation programs are not all the same. A commercial defragger, such as Diskeeper’ will move the data closer to the centre, which again reduces head movement. Freebies tend to leave it in random locations on the disk.
The best way to use a freebie is to defrag, then reboot, and then defrag again. This helps to shift the data together. Commercial defraggers work in the background.
If you have three disks (physical or logical) you should keep one (C: ) for programs; the second for data (say F: ); and the third (say G: ) for defragging. You then periodically copy all your data from F: to G:. Delete F:, and when you copy it back again it will automatically be in contiguous blocks.
In the two examples quoted leaving it for so long probably left the FAT itself fragmented, making the disk even slower.
Solid State Drives need a commercial defragger specifically designed for SSDs. Other defraggers will reduce their life expectancy.
Ken
