This recipe will change the default location that windows installs programs. I'm a two hard disk-drive guy with numerous partitions. I like to keep my main drive for my OS and install programs on one of the partitions of the main drive.
So if you want to change the location where you install programs but windows always wants to install programs to "c:\program files" and changing it everytime can be a pain. After you back up your registry, this is how you can change this default location.
1. Navigate to:
2. Find ProgramFilesDir whose default should be C:\Program Files
3. Change this to whatever directory you wish. I changed it to D:\Program Files for example.
Remember you have to reboot for your changes to show.
For more info look here