You cannot just move programs. Windows uses something called a registry, that keeps track of programs. Moving programs by simply copying and pasting the files won't work because the registry won't know you've moved them. You can uninstall your programs from the C: drive and reinstall them to another drive, but I wouldn't recommend installing programs to an external drive.
If you just want to save your files (ie. your photos/pictures etc) to your portable hard drive then that is another matter and easy to do - follow these instructions enter link description here