Change The Default Location For Installing Apps In Windows As the size of hard drives increase, more people are using partitions to separate and store groups of files. XP uses the 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 hack. Go to :- - Start > Run - Type regedit - Go to this directory HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion - Look for the value named ProgramFiles Dir. 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.