After defragging my wife's HP550 laptop with Windows Vista Home Premium O/S our freespace increased from 15% to 26% on a drive with 102 gig available.
I paid $14 to 'The Answer' guy just to find out 'it's not possible'.
Just so you won't think I am crazy, I am a retired 30-year mainframe Cobol programmer who knows how to read a report.
Background: I ran CCleaner (Piriform) before defrag.
I then ran Defraggler (Piriform) analysis; reported 15% freespace.
I then ran Defraggler complete defrag; took about 2 hours.
Defraggler then reported 26% freespace; ie. we gained about 11 gig of freespace!
Any suggestions appreciated. I am seriously considering a system restore if we find things missing. Hindsight is 20/20 but I REALLY wish I had printed before and after reports; maybe Piriform stores defrag reports? Piriform wont talk to me unless I have an account; but that is another story.