I have a laptop with some bad viruses on it. I've heard that some viruses can remain on a hard drive even after a reformat. So I was wondering about sanitation tools and if thats the right way to go before i reload the OS on this laptop. I've never actually used any kind of sanitation tool so it will be a new experience for me. I'm hoping to get some insight on this from someone that has done this before.
What you've heard is not right when installing windows format and partition the drive and you will be fine. With formatting you erase the whole drive so nothing transfers over to your new fresh OS install
There are still Virus which can infect the master boot record (first sector of hard disk) this is almost impossible to remove if booted from Windows and re formatting the hard disk will not remove this as the MBR is not re written by Formatting
Possibly booting from your Win (7) DVD, remove all partitions. Reboot and re create the partitions.
But This looses all your data
An alternative I used was to boot from a WinPE CD and run mbrwizard (or similar product) to re write the MBR (Master Boot Record)
Norton detected the problem but could not repair it
I can tell you of the tools that I use regardless of the system being clean or infected.
"darik's boot and nuke" is a good favorite of mine. It does take a while to complete, but i've never had any problems with it.
Another good solution that is MUCH faster is Secure Erase. Some drives may not be supported. You can use both tools if you want.
Note that both of these tools will completely wipe all partitions, so you will not be able to restore your system to factory settings unless the image is on another drive, but I don't see why that drive cannot be infected as well.
If these tools fail, you may try booting into a Linux Live disk and using the dd command to wipe the drive. This would be the last choice on my list, but it works.
As for the (Master Boot Record), I am almost certain that both tools remove the MBR, but you can always run a command to rewrite it by going into a windows recovery console and typing fixmbr. I can get to mine with my Windows XP Disk, Im assuming W7 still has this function.