I am administrator in my Windows 7 PC.
How can I make an installed program invisible for a certain user (in the Program Files folder)?
I´d recommend changing NTFS permissions. Right click on folder, then Security. That way you can restrict visibility for the folder AND disallow opening it or running anything in it , or whatever. Infact, you can go into more detail than you´ll probably ever need in a home PC.
Some background on NTFS permissions here.
If the user you want to hide folder from is not very familiar with computers.
Then you could: 1. right click on folder, and choose hidden. close that window.
Go to control panel, and to folder options. Find and turn on option to hide hidden folders.
From that users start menu right click on shortcut and delete so they do not see it there either.
(This should be done from the users account, not You/Admin)
Here is some more info on password protecting folders and files.