default installation directory in fedora
 

when i use yum to install some packages, where does it install the software. How can i change the installation directory during installation or permanently.

why do you want to change the location? There is VERY rarely any reason at all to do this. You can see what's in an RPM with "rpm -ql firefox" for example. But I would urge you to not care. There is no "Program Files" directory per se, files from packages get put in directories based on what they are, not what packages they are from. programs go in a /bin/ folder, libraries go in a /lib/ folder, documentation goes somewhere else again etc.

To give you a better understanding how Linux is organized when it comes to locations of files you may want to have a look at the Filesystem Hierarchy Standard.

I get the following error when i type "yum search firefox" in fedora 13 terminal. I want to install latest firefox. What should i do. My computer is new- I have not installed or created any other files here.

Fedora 13 is out of date and not supported anymore. That may cause your issue. Install the current Fedora 16.

If (when) you get your new Fedora, try to stick with what's in the repository. If you add other stuff, you become responsible for sorting out the dependencies instead of yum, and that can get quite confusing.

If you type "rpm -qi firefox", the information you'll get includes "Relocations: (not relocatable)", and that applies to most software.