First of all, you need some network informations which you can get from windows.
In windows click start menu. Click run.
Type cmd. Then type ipconfig /all
Write down those information(ip, subnet, default gateway and DNS). Or save them in a text file and mount from Fedora Core.
Click System>Administration>Network. The window is as below:
Double click the eth0 device. A window will open like this one
You have to uncheck the tickbox saying Controlled by Network Manager. Enter ip address right to the Address.
Subnet mask and default gateway.
Now click DNS tab, The window is shown as below:
Click manula proxy configuraton and then enter your settings.. and you are done...