This is, in every common operating system, the purpose of the PATH-variable.
If you are bound to windows, there is a better way to do it case you want to use that extensively: I used to have it set up for A LOT of programs, so I could start my programs by Win-R (like Start->Run or on the command line), type in a few letters of the executable name, take advantage of the MRU-List and start the application.
The drawback of adding all paths of those executable to the path is that it slows down the command execution: Everytime you call a program, all paths have to be scanned. Therefore, the PATH variable should only be used for directories that contain several executables, like a "bin" or "tools" directory.
The better way is to create a proper entry in the registry, many program installers do that by themself, BTW.
is the place to go.
You will already see a lot of entries. AFAIK, this would also allow to have two different commands starting the same program, but in different working directories, or different properties.
Unfortunately, I have not yet found any information from Microsoft/MSDN about the parameters one can find, like
BlockOnTSNonInstallMode. We can only speculate on that.
This will also allow you to "rename" the program without actually renaming the executable file (which could get you in trouble if you update it or if it's part of a larger suite) and migrate smoothly if you switch to another favourite application for a certain task. I had vlc and IrfanView start when I typed "wmplayer" and "ACDsee32" accordingly out of habbit/mistake.
THIS is the most exhaustive I ever found about it.