Boot Sector Viruses
Do you happen to have met boot sector repair problem? In case you do you can see my point. I just would like to won you that approximately 75% of all hard drive booting problems, partition access failures, and generic "hard drive failures" are the result of an overwritten or otherwise corrupted Master Boot Record or partition boot sector. How to solve the problem? Looking for a partition recovery software solution youy can find out tons of links to choose from. You can use the Exact data recovery software that can extract needed data from failing drives, BootMaster Partition Recovery, designed as an expert system to provide a safe, easy-to-use method for recovering from MBR and boot sector related failures on Windows 9X, 2000 and XP computers, Avira Boot Sector Repair Tools or something else.
What is a boot sector? If you dont know all disks and hard drives are divided into small sectors. The first sector is called the boot sector and contains the Master Boot Record (MBR). The MBR contains the information concerning the location of partitions on the drive and reading of the bootable operating system partition. During the bootup sequence on a DOS-based PC, the BIOS searches for certain system files, IO.SYS and MS-DOS.SYS. When those files have been located, the BIOS then searches for the first sector on that disk or drive and loads the needed Master Boot Record information into memory. The BIOS passes control to a program in the MBR which in turn loads IO.SYS. This latter file is responsible for loading the remainder of the operating system.
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.
Creating a system disk. When disinfecting a boot sector virus, the system should always be booted from a known clean system disk. On a DOS-based PC, a bootable system disk can be created on a clean system running the exact same version of DOS as the infected PC. From a DOS prompt, type:
SYS C: A:
and press enter. This will copy the system files from the local hard drive (C:) to the floppy drive (A:).
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 bootdiskmakeboot a: and then click OK. For example:
d:bootdiskmakeboot a:
Follow the screen prompts to finish creating the bootable system disk. In all cases, after the creation of the bootable system disk, the disk should be write protected to avoid infection.
(via antivirus.about.com)
