I have been unable to COMPLETELY defrag my hard drive. I have no virus, no spyware, no malware. I've used the defrag system in my WinXP home to no avail. Lots of framented files left. System tells me to defrag. The report tells me that C:\documents and settings\all users\applications amounting to 12.28 gb cannot be defraged. Has anyone had this trouble and if so how was it resolved.try doing it in safe mode......f8 on boot......also diskkeeper lite is the favorite of the year........are you using .......norton anti-virus........But try deleting ALL of the C:\Windows\Prefetch files first of all.

You might like to try out the 30 day evaluation copy of Diskeeper 9 Professional (not the Home version) and USE the program's Frag-Shield add-on to see if there is a PROBLEM with the Master File Tables or MFTs.

I will try that. Thanks.Well, I've tried all the suggestions and still cannot completely defrag my C drive. I tried Diskeeper and O&O both both programs failed to completely install themselves. I must assume that my C drive cannot be fully defraged.. I still have 12.28 GB fragmented files that stay fragmented. Still my computer tells me that the system should be defraged. Any thoughts? Thanks to all who responded.If you look under details after defrag you should be able to see the files that weren't defragged.
Defrag in safe mode with nothing running at all.
Also turn off screensavers & power saving options etc.
Turn off antivirus stuff too.

I believe defrag can have a problem if the disk is too full but I haven't EXPERIENCED it yet.I would guess that you do have a virus somewhere in that folder. Try a couple of on-line scans from Panda and Housecall and seee if they find anything.

If you are using Norton make sure that there are no file excluded from scanning on the file exclusions page.Just wondering about free-space in general. So try this and see if it helps:

"Run Disk Cleanup and remove all but the last restore point. See if your System Restore cache and Recycle Bin size is set at a reasonable level (Say 1024Mb) on each drive, and reduce the IE Temporary Internet Files cache and History cache to the MINIMUM. Install CCLeaner and clean out all of the junk files. Unhide all files and folders and remove the hotfix uninstallers ( $NTUninstaller$ ) from the hidden C:\Windows folder and remove their entries from Add-Remove programs. Then remove the contents of:

The C:\WINDOWS\Downloaded Installations folder
The C: WINDOWS\SoftwareDistribution\Download folder
The C:\WINDOWS\Temp folder
The C:\Windows\pchealth\Datacoll folder, and...
The C:\Windows\Prefetch folder

(You can add these folders to EmpTemp if you have this program installed.) Then run chkdsk and defrag."