I'm visiting my friends in Florida and wanted to help them by doing a defrag on their system. I downloaded Defraggler and ran Analyze which posted a result of 51% fragmentation. I then ran defrag and after many hours the result surprised me. Fragmentation was at 50% - i.e. it had only improved 1%. I feel the only explanation is that the drive is partitioned and I'm not sure how to deal with this. They have Vista.
See the image below. Any advice will be greatly appreciated.
I'll give my best guess.
That mass of red blocks lies in the area Vista places System Volume Information (restore points/shadow copies). Place your pointer on some. Are they?
If so, they cannot be defragged cos they are protected system files. The pc has maxed out the SVI, hence the massive frag count.
Install CCleaner and delete some of the older points using CC's System Restore Management. (CC ➢ Tools ➢ System Restore.)
Watch the frag count drop, but in time it will rise again. The SVI will again max out but should not impair performance.
So in the end, nothing will be gained from reducing the frag count by eliminating older restore points. Just learn to live with the frag count. As long as the other files are not fragged the system should run fine.
Next time, for super fast defrag try:
File-only defrag 
or Quick Defrag 
TY kroozer for your help. I took your advice. Also, thank you for the tip regarding file-only defrag - I have never realized that option.