When you download a program, how do you decide whether you should save
it or run it? What is the difference? Why does it make a difference?

Hello bobt213-ga,

The only time you should save it is if you want to keep the
installation file on your computer (so that you can install it again
in the future). You might also want to burn the installation file to a
CD-ROM or copy it to some other computers if you are installing it on
multiple computers. Another benefit of saving it is that you can run a
virus scan on it before running it (although some anti-virus programs
will scan it even when running it).

Generally, if you trust the program and know what it is, running it is
the better way to go. The program is still "saved", but it gets put
into a temporary directory that is deleted when your temporary files
are cleared. In order for the program to be run, it is necessary that
it is saved somewhere on your computer first. By choosing "run", the
computer chooses a temporary location to save the program to, and then
after you install it, the installation file can be cleared. This saves
memory space because most people will not need to install the
downloaded program again (it is much easier to get it again from the
website).

I hope this helps clear up and explain the difference. To summarize,

The reason someone would choose run instead of save:
-saves hard drive space because the installation file can be deleted
after installing
-quicker because you don't have to choose a directory to save to, and
then find that directory to run it

The reason someone would choose save instead of run:
-maybe they have to install the file on many computers (and they do
not want to download it that many times)
-you can keep a copy in case your computer ever crashes (although the
copy might have to be saved somewhere other than your hard drive
because if that crashes... there is no point to saving it anyway)
-to run a virus scan on the program before running it.

All the best,

tisme-ga

If you save it, it will ask you where you want to save that file
before you run that programs.  You wan decide whether you want to run
it now or run it at anytime you like.  And you can run it again and
again.

If you run it directly, it will save in temporary folder and you can
run it once.  The next time, you need to download it again if you
decide to run it.  If you not empty your temporary folder,  may be you
can look into that temporary folder and run it again(but you must know
that if in temporary folder, the name of that file is random and some
time you can't open it again).