Note: Disinfectant and Gatekeeper are free Mac Anti-Virus programs but they have been discontinued. The final version of Disinfectant was 3.7.1. Thanks to John Norstad at Northwestern University for providing and updating this useful program for 9 years! While it is effective against old viruses, it cannot remove Word Macro viruses or the recent Autostart Worm, which are the two most problematic kinds of viruses on the Mac platform in recent years. If you need up-to-date commercial Virus protection, try either Virex or Norton Anti-Virus. If you still want Disinfectant and Gatekeeper for older machines (and those with Word 5 or older), here they are... Disinfectant and Gatekeeper.

Installing virus protection on your hard disk

1. Copy the "Disinfectant" program to your hard disk and run the program. In the menu at the top of the screen, choose Protect and select Install Protection INIT. This puts a small self-loading program inside your System folder (Extensions folder) that checks for the activity of viruses automatically.

2. Copy the file "Gatekeeper Aid" to your hard disk and put it in the Extensions Folder within the System Folder. This is another self-loading program that offers additional protection.

3. You must restart your system before these "INITs" becomes active. When the computer is starting up, make sure that two icons appear at the bottom left of the screen.

The first symbol is a and the second is a . These show that Disinfectant and Gatekeeper have loaded and automatic protection of the hard disk is now installed.

You can still run Disinfectant occasionally to check for viruses that may be laying dormant.

Scanning your floppies for viruses

1. Run the "Disinfectant" program from the hard drive, and then insert the suspicious floppy disk(s). Click Scan or Disinfect as above.

2. To learn more about viruses, read the thorough "Help" information within the Disinfectant program. The history of viruses is interesting in twisted sort of way.

3. Pass along copies of this program to anyone with a Macintosh. It is free and legal. The program is updated occasionally to keep up with the latest viruses. The current version is 3.7.1

Removing viruses from the hard disk

1. Insert the locked "Anti-Virus" disk. Because it is locked, it cannot be corrupted by viruses. (To lock a disk, flip up the write-protection tab in the top right corner of the disk, so that the hole is open. To unlock, flip the tab down and the hole will be closed.)

2. Run the "Disinfectant" program and select the hard disk of your computer as the disk to be checked. Click "Scan" to examine but not fix your disk, or "Disinfect" to examine and remove any recognized viruses.

3. Once completed, read the report. It will tell you whether or not you had any viruses infecting your system. If you did have viruses, you will also have to remove viruses from all of your floppy disks, which are probably also infected, but first you should install virus protection on your hard disk.