antivirus definitions -

If they are connected by a CAT 5 cable in a network configuration you can just MAP the drive in the other machine and Scan it along with your computer when it does its routine AV Scans.

If they are not connected you are up against it as it will require you to install AVG on the unconnected computer and then manually down load all the AV Definitions and copy them to some form of media that can be moved between computers and then install them to the second computer and when this is done you can then run an AV Scan. But every week you'll have to download the latest Definitions and copy them across and then Scan the computer.

If it isn't connected to the Internet or LAN and you don't use written Floppies or Cd's it really stands very little chance of becoming infected with anything at all, it should remain clean, it is only when you share files/programs that you create yourself or others create that you run the risk of getting it infected.

Col

If the other PC is never connected to the Internet there's no need to even install antivirus software.

However you can download definitions from just about all the antivirus makers & just run the .exe once downloaded.

For Norton go here
http://securityresponse.symantec.com/avcenter/defs.download.html

If the two computers are connected it is simple.
you select in avg the other computer's HDD and scan it. If there are not a connection you must install the avg to the other computer and download from grisoft the latest virus definition and copy to the other computer for updating the avg.

As others have said download the defination file and manualy install it via sneaker net.

By the way. If that computer has a floppy, cd or usb drive accessability it needs antivirus.

Lee