windows - What are the Proper Steps for Complete Restore of Computer after Being Infected?

I feel that many the average computer users come across a similar situation to what I am in now. A situation where these users find that their computers are infected with difficult to remove viruses, malware, spyware, or etc. Most often it seems that it is more time and/or cost effective for the average computer user to fully delete and partition the hard drive, and then reinstall the operating system.

I am in a situation now, where I would like to start fresh with my computer, but I am reading online that simply reinstalling Windows (including the partitioning and deleting of the everything on the drive) can sometimes not be effective in removing certain viruses. I then read further, and heard about, zeroing the hard drive (think Darik's Boot and Nuke, it fills the drive with random data) which can help in data deletion and also virus removal when doing a complete reinstall. (Although maybe I am getting this wrong?)

I am also aware that viruses may infect files that I have backed up on an external drive. Which would make it somewhat pointless to put those backed up files back onto a "fresh" computer as those files may reinfect the "fresh" computer.

I feel many people find themselves in similar situations and do not know exactly what to do or how to properly start "fresh" with their computers. Hence, why I ask the following questions.

My Questions:

1. What is the proper order to perform a complete reinstall?

   
   
   
   
   • Do you zero the drive first, then do the OS reinstall?
   
   
   • Or do you do the OS reinstall and then zero the drive?
   
   
   • Or do you have to reinstall the OS, zero the drive, and then reinstall the OS again?
   
   



2. Is manually filing your hard drive until full (with something like multiple jpg images) the same as zeroing the hard drive with a utility like Darik's Boot and Nuke? And is this helpful/effective in malware, spyware, virus, etc. removal or just an unnecessary step?




3. How thorough does one need to be with scanning/testing backed up files on an external hard drive before putting them back on to the newly restored computer? (Note: the backed up files where backed up from the computer was infected).




4. Can malware, viruses, spyware, etc. go from one computer to another if the computers on the same network or even if the computers are just hooked up to the internet through the same wireless router? (Is it likely?)

   
   
   
   
   • If a person has two infected computers and they completely restore one of them (full deletion of all data on the hard drive, a hard drive wipe, and an operating system reinstall) should this person also completely restore the second computer, in worries that viruses, malware, spyware, etc. may go through the router or network from the second, infected computer, to the first, newly restored computer?
   
   

Answer

What is the proper order to perform a complete reinstall?
Do you zero the drive first, then do the OS reinstall? ..

Make sure you have CD/DVD to re-install from, or your computer has a recovery partition. You might need both. Boot to the cd/dvd and reinstall. When reinstalling you can repartition the hd.

I would not even waste the time copying/zeroing out a hd. Repartitioning &Or formatting is good enough. Zeroing is mainly for making recoverablitlity harder if you give your hd away. Just do not wipe out your recovery partition (unless you got a cd).

How thorough does one need to be with scanning/testing backed up files
on an external hard drive before putting them back on to the newly
restored computer? (Note: the backed up files where backed up from the
computer was infected).

Before you move them back make sure your AV is installed and up to date. Then thoroughly do a deep scan. I would check for shadey files and delete them, including any exe files.

Can malware, viruses, spyware, etc. go from one computer to another if
the computers on the same network or even if the computers are just
hooked up to the internet through the same wireless router? (Is it
likely?)

Highly unlikely.

If a person has two infected computers and they completely restore one
of them (full deletion of all data on the hard drive, a hard drive
wipe, and an operating system reinstall) should this person also
completely restore the second computer, in worries that viruses,
malware, spyware, etc. may go through the router or network from the
second, infected computer, to the first, newly restored computer?

No. You have to find what caused it if you can. Was it an email? website? Would be easier to stop it again if you know where it came from and how it got in you can stop it in the future.