An additional built-in security feature of most computers is the ability to force the computer to always boot from the hard disk, even if a floppy disk is in the disk drive.
Some purchased security programs include a feature to "lock the hard disk" or to "prevent booting from a floppy diskette." Using such software to lock the hard disk and prevent booting can give a false sense of security. Typically, purchased security software can provide protection for the hard disk from access using DOS or Windows, but the computer can still be booted by using a floppy diskette. This means that a virus could be installed on the hard disk even with the security software in place.
Use your computer's built in security to prevent booting from a diskette. You will need to check your computer's manual on the procedure to do so (as each computer is different), but typically you can either disable the A: drive's boot ability, or set the computer's boot sequence from A:-C: to C:-A:, that is, boot from the hard disk first. It is important that you disable booting from a floppy diskette to prevent virus infections.
Once you disable booting from a floppy diskette using the computer's CMOS settings, make sure you enable either the setup password or boot password to prevent someone from accessing the CMOS and enabling booting. You computer will be unprotected if the computer is booted via the floppy diskette.
If you cannot disable booting from the floppy diskette drive on your computer, make sure you enable the boot password, and instruct the staff to check the A: drive for diskettes before entering the password that allows the computer to boot. This will reduce the chance of a boot virus being installed from a infected diskette.
There are other ways of preventing booting from the floppy disk, of course. Simply locking the computer's box in a locked closet, or using a hardware diskette lock will work