How to avoid boot sector viruses. Commonly, infected floppies and subsequent boot sector infections result from "shared" diskettes and pirated software applications. It is relatively easy to avoid boot sector viruses. Most are spread when users inadvertently leave floppy disks in the drive - which happen to be infected with a boot sector virus. The next time they boot up their PC, the virus infects the local drive. Most systems allow users to change the boot sequence so that the system always attempts to boot first from the local hard drive (C:\) or CD-ROM drive.
Disinfecting boot sector viruses. Boot sector repair is best accomplished by the use of antivirus software. Because some boot sector viruses encrypt the MBR, improper removal can result in a drive that is inaccessible. However, if you are certain the virus has only affected the boot sector and is not an encrypting virus, the DOS SYS command can be used to restore the first sector. Additionally, the DOS LABEL command can be used to restore a damaged volume label and FDISK /MBR will replace the MBR. None of these methods is recommended, however. Antivirus software remains the best tool for cleanly and accuarately removing boot sector viruses with minimal threat to data and files.
If the disk has not been formatted, the use of FORMAT /S will format the disk and transfer the necessary system files. On Windows 3.1x systems, the disk should be created as described above for DOS-based PC's. On Windows 95/98/NT systems, click Start | Settings | Control Panel | Add/Remove Programs and choose the Startup Disk tab. Then click on "Create Disk". Windows 2000 users should insert the Windows 2000 CD-ROM into the CD-ROM drive, click Start | Run and type the name of the drive followed by bootdisk\makeboot a: and then click OK. For example: