Windows compresses files and folders (NTFS partition) that are not accessed
very often, explorer shows these files/folders in blue.
Compression can be turned on or off on a folder by folder basis.
Just select a folder, right click and select Properties, General Tab,
Advanced Button.
In the Advanced Attributes window you will find the Compress options near
the bottom.
Check or Un-check the Compress contents option.
Also when in Explorer select: Tools, Folder Options, View, Advanced settings
to see options related to colors.
How To Use File Compression in Windows XP
http://support.microsoft.com/kb/307987
JS