After installing RH7,3 on my laptop, i find out that most applications didn't work, but i just had a message on my system that i was using the wrong window manager (the hell do i know how i did that...but it is me. So it is not so surprising.)
How can i get that window manager back to spec? I use Gnome and KDE.
thx

The window manager you run should have no effect at all on what applications you can run.

Some applications (ones which reside in something like the windows "system tray") require with the KDE kicker, Gnome panel or Blackbox slit, but this shouldn't cover "most" applications.

What errors do you get when you try to run apps?

well nothing... i double clic, triple clic and clic again but nothing... modzilla and other stuff. Some works but other doesn't.

Some programs don't have a gui, so when you double click the symlink or even the app itself nothing will happen. You would open a vterm and type (for example) dvgrab --autosplit... and then the program will do it's thing. For those that are supposed to work inside a gui, you would have to make sure that you make them executable (either open a term and cd to directory and type foo -R 777 or in an X window, right click the file and choose properties, in there make sure the box for Exec is checked).

If you are more specific on the programs it's happening on, maybe we could be more specific on the answers we provide.

If you are talking about when you first install your distro, and have the default icons on the desktop there, and you double click those and nothing happens, then I would make sure that they are symlinking to the correct files.