Disable Compression on XP, NTFS Partition, Disk Cleanup

On an NTFS partition, Disk Cleanup can compress old files
to save space. But calculating the savings and performing
the compression often take a long time, and on some systems,
Disk Cleanup hangs during the process. If that happens, or if
you don't care to wait, use this Registry tweak to disable the
compression: Delete the key
HKEY_ LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\ CurrentVersion\Explorer\VolumeCaches\Compress Old Files.