Most installation programs will actually download stuff from the internet so if you wipe your internet it won't load. Some will let you download the "full" installation file and then it will work.
Most antivirus packages today only install a portion of the application when you grab the exe file. Most of them require an Internet connection to fully complete the installation of the software.
AVG has "full" installation files that you can use to load the program. Download the one you want before you blow away the internet. It won't have the most up to date detection files but they will be fairly new and good enough to get started. When you get network installed it will update to the latest versions....