Or perhaps you could learn to read the readme.txt file properly that is often included with the emulators.
For the record I haven't experienced the problems of the type you seem to be alluding to, and thus don't see the need to try to say that a installer should be done.
The emu programmers do this as a hobby and as such if they don't want to do an installer which wouldn't be needed, then they shouldn't.
To manually install, say 1964:
Download
Copy all plugins from say PJ64 into the plugins folder of 1964
Set up all plugins
Load 1964
Configure Rom path
If game is playable, you can play it
If not, then words to that effect will be on screen for you to read
Hope this helps
