When installinga new program, how can I utilize the free space on my 2nd hard drive ?

When running the installer for the new program, the install location can usually be set to wherever you want by selecting the "Custom" installation option instead of "Normal". Set the install location to be on the second drive.

Some installers do not allow changing the installation location. To place programs using these installers on the second drive, they have to first be installed to wherever the installer wishes to install it. Then the program's files can be manually moved to the second drive and any path references in the Windows registry or the program's configuration files are updated to reflect the new location. These types of program's can be problematic to move as they often have other hard-coded assumptions about where the program exists (C:\Program Files.. etc.) and will not function correctly when moved.

To facilitate backup and also service ease if you were to ever take the computer to someone for repair, consider moving your data files to the second drive and keeping all the programs installed on C:. If the new drive is larger than the old drive, cloning software such as Acronis True Image or Clonezilla can be used to copy the entire contents of the old drive to the new drive. The drives could then be switched physically so the new larger drive is C:.