How to Remove a Boot Sector Virus


Has your computer been acting strange lately? Has it been running  slow, or telling you that your computer needs a certain program? If so  it may have a virus. This article deals with ones called Boot Sector  Viruses. These reside in the sectors that are used to start your  Operating System. Some of the viruses that reside here also store  themselves in your BIOS so they are booted even if you have just done a  clean install.


Steps 

  1. Remove any important files and shut down the infected computer. You can  not begin to remove the virus if it is in the RAM in your computer. 
  2.  
  3. Download a new BIOS flash utility (must be DOS version) and copy it  to the bootable floppy you are about to make. These are found at your  motherboard manufacturer's website, or at your computer manufacturer's  website if you have a laptop.

  4. Create a bootable floppy from an uninfected computer. Then write-protect the floppy.
      
  5. Remove the HDD (hard disk drive or hard drive) from the infected  computer. Be sure to remove all of the static electricity from your  self by touching the metal case.
      
  6. Start up the infected computer with the bootable floppy in the floppy drive.

  7. When the BIOS setup page shows, Push the corresponding key to change the Boot Order.
     
  8. Set the Floppy drive to boot first.
      
  9. Flash your BIOS with the utility provided by the manufacturer. DO  NOT TURN OFF YOUR COMPUTER UNTIL THE UTILITY TELLS YOU THAT YOU CAN.  DOING SO BEFORE IT IS FINISHED MAY PERMANENTLY DAMAGE YOUR COMPUTER.

  10. Find out which company manufactures your HDD and see if they have a  utility that will do a Low-Level format. This part is important because  it deletes everything from your hard drive so that no one can get it  back, including the virus. Some common HDD manufacturers' tools for  doing this can be found here.
       
  11. Run the formatting utility provided by your HDD manufacturer.
      
  12. Reinstall your Operating System of choice however you want to.
And most important thing is that use trusted software to remove  virus else you will be in more trouble(if that softwre is infected).

Tips

  • To  make the bootable floppy in Microsoft Windows, go to My Computer, right  click on your floppy drive (usually A:\ or B:\), click "Format...",  then find the box that says "Create a MS-DOS startup disk". Then copy  the flashing utility, and the low level format utility.

     
  •  
  • If you feel uncomfortable completing any of the steps, take your computer in to a specialist.

Warnings

  • Be  sure to write protect the floppy and remove the HDD before you flash  the BIOS, because any virus that is residing in the boot sector of your  HDD may copy its self over top of the BIOS you just flashed.
  •  
  • A Low-Level format will erase anything and everything on your HDD.  It does this because it erases the whole disk, and not just the File  Allocation Table (FAT) which is the directory for the hard drive. Its  kind of like a telephone directory. When you delete things or do a  format in Windows or DOS, known as a High-Level format, it tells the  FAT that there is nothing there anymore, but leaves the data on the  disk. A Low-Level format or delete tells the FAT that there is nothing  there and then rewrites the sectors on the HDD where the file was.  Because of this there is no possible way to get your data back after  this process is complete.
  •  
  • If you reboot your computer before the flash utility is finished  with your BIOS, it will corrupt the BIOS and render the computer  inoperable. You will need to get a new motherboard if this happens.