this is the message i get when i try to yum install anything:

Loading "installonlyn" plugin
Setting up Install Process
Setting up repositories
core
Cannot find a valid baseurl for repo: core
Error: Cannot find a valid baseurl for repo: core

please help

Go to /etc.
Using vi or nano read and edit yum.conf also
cd yum.repos.d

edit the repo files there to put in the address of a mirror site near wherever it is you live eg: aarnet.edu.au planetmirror.com.au etc. Then see if these repos (repositories of files) are found. If so ..if not repeat until they are.
Sorry using SuSE at moment not Fedora, so hope this helps.

this may be a stupid thing to say but i am a newbie. i dont have internet right now. thats another problem im having. anyways, i dont know if i need the internet to be able to yum install anything

I'm just learning Fedora myself, though I have used SuSE for years.
My impression is that yum looks on the internet to update and install files and pirut which adds/removes programs grumbles if it doesn't have an internet connection.

If it is asking you for a baseurl, it DEFINITELY wants to connect to an internet (URL) address. So you have to set this up first.

If using KDE try kinternet, I'm not sure what the equivalent command line is in gnome. As I use a proxy server with fast internet cable (flatmate is elec.engineer and can't survive without this apparently!), I'm a bit rusty on dialup setups. If you have installed gnome, I'm afraid you are on your own as I don't have a PC using it at the moment.

Maybe someone else can help?

Anyway, stop doing this and get on with Christmas cheer etc.

Best wishes for New Year.