I am trying to connect through my computer to the GUI web interface for my server, and it's not going at all.
So, I ran: mii-tool, and it showed: eth0: no link

Can anyone help fix this?

you have no ssh access? better still you can try installing webmin using yum

I really am not a programming person, I just chuck head for this one,

if you have ssh access to your server, simply download putty
run it, login with your credential and you will end up with a linux version of cmd

use google incase you need clarification on any command.
since you have centos 5, then yum is your package manager

sudo yum install apache
sudo yum install php
sudo yum install mysql-server

etc

when an update becomes available just
sudo yum update