How do I save programs on external hard drive?

I need to have more space on my pc and would like to put programs like Photoshop on an external hard drive. As you can tell by my question I'm new at this. THanks

when installing programs most (but not all) will ask what directory to save it to

normally its C:/Program files/

if you change that directory to one on your external drive then that should install the files to the specified directory.
E.g F:/programs/

ok but how do I do that? Like I said I'm new, really new :-{

i will use photoshop as a example

if photo shop is already installed

1. Back-up any files you want to save (from photoshop)

2. go into control panel > add remove programs

3. uninstall photoshop

4. run the set-up CD / Double click the installer

5.during install it will say choose directory by default this will be C:/program files/

6. change that to the desired directory E.G H:/programs/
(H being the external drive letter / PROGRAMS being the folder you want it installed in)

7. Complete installation.

If photoshop is NOT currently installed, START from STEP 4

THank you