Solved How to wipe MBR on infected hard drive

So - I offered to try and fix a relative's laptop that seemed to be dead. It was dead! No power even with new power supply. So I offered to take the hard drive out and put it in an enclosure, retrieve the files and then format it so it could be used as an external hard drive.

On plugging the drive into my laptop, my antivirus blocked a virus. I scanned the now external drive and it found 30 viruses including 2 trojans. It removed some and I reformatted the drive to Fat 32, scanned again and nothing showing.

My question is - is this drive safe to use now? I understand that some viruses can live in the MBR and not be detected by antivirus. So if I have formatted to FAT32 will this be enough to wipe the MBR? Thanks.

Open up disk manager and delete all the partitions if it has any then format it.

Fdisk /MBR from CMD prompt will do it

Thanks. So I just open command prompt and type "Fdisk /MBr" ? The drive is inside an external case and plugged into a usb on my laptop so don't want to run the command on my internal drive! Do I need to add anything to the command to make sure it does it to the right drive? Thanks.

You would need to have the infected disk in on its own to run fdisk /mbr booting a install dvd cmd prompt or you can use partitioning software to do it FREE Rebuild MBR, repair MBR, fix MBR or MBR recovery with free EaseUS Partition Master

The safest method to clean wipe your HDD including Sector 0 where the MBR and partition table reside is to do a low level format using HDD LLF Low Level Format Tool which has a graphical User Interface. It will show your system drive and all other Internal/external drives connected and you can select a specific drive which has to be zeroed. You cannot go wrong unless you are blind. Download the Windows executable version (works without installation) 4.40 from here HDDGURU: HDD LLF Low Level Format Tool A total wipe can take many hours depending upon your drive's capacity but you will get a clean drive as it left the factory (before factory format). Once a low level format is completed do a regular format. A quick format will do since you already have a clean drive.

Thank you all. Jumanji - have downloaded it from your link - many thanks. There is a lot of confusing info out there on how to erase the MBR! So far I have just used parted magic and done external dd on the entire disk. I wasn't sure if that wiped the MBR or not. There is actually an option on parted magic to erase MBR but it was quite quick and I haven't seen it mentioned anywhere else so not sure if it is actually a viable option. Anyone know?

If you are very inquisitive, you can download bootice from 【BOOTICE v1.3.3.2: 功能强大的启动维护工具】-子逸轩 and examine sector 0
( download x86 version if your system is 32bit and x64 if your system is 64 bit)

Bootice explained in my post #7 here: Lost partitions! Solved - Windows 7 Help Forums

You can examine sector 0 with it.

Run the mouse pointer diagonally across to select all fields > right click > Fill selection >Fill with 0x00 >OK > Save changes




You have effectively zeroed Sector 0

Caution: Always make sure you are making any changes to the correctly selected drive.. As an added precaution always save the sector/s to which you want to make changes. If need be you can always restore the sector/s with that backup.

If by mistake you kill sector 0 of your system drive - Gone with the wind. Your system will no longer boot.

Thanks! Yes am ultra cautious at selecting the correct drive I have HDDGuru running now doing the low level format. Is it the same as running DD on Parted magic? If so I've done it twice now lol.

Hazel123 said:

I have HDDGuru running now doing the low level format. Is it the same as running DD on Parted magic? ......

Click to expand...

I don't know for I had never used Parted Magic. I always zerowipe my 500GB trial drive (on which I do my experiments) with the HDD Guru Low Level Format Tool. Since that takes almost 8 hours on my old rickety slow PC, I leave it running overnight.

I gave you the bootice just to check all sectors and satisfy yourself that all sectors have been zeroed and completely. Other than that I always advice that users save all the important sectors in MBR drives as well as GPT drives. In case one faces partition related problems/ corrupted MBR/Volume Bootsectors simply restoring the sectors with the backup can resolve the issue.

Thanks. Yes it did take all night, but all sorted now. Thank you.