As the size of hard drives increases, more people are using partitions to separate and store groups of files.
Windows Operating systems use “C:\Program Files” directory as the default base directory into which new programs are installed. However, you can change the default installation drive and/ or directory by using a Registry Editor.
changing the default installation directory in windows systems gives you the ability to store the installation files on the different drive or location. this helps you in controlling the C:\ drive space of the system.
Run the Registry Editor (Regedit)and go to
Look for the value named ProgramFilesDir. by default, this value will be C:\Program Files. Edit the value to any valid drive or folder and XP will use that new location as the default installation directory for new programs.