How Do I Run An Anti-Virus Scan If I Can't Boot?

Most of the self-help books that have been written about XP say the same thing – if you can’t start XP in safe mode you might have a virus so run an anti-virus program. Well, all of my anti-virus packages were downloaded, so I have no install disks. But even if I had an install disk, if I can’t boot Windows, or I can’t connect to the Internet, a disk won’t do me any good. So how do I run an anti-virus scan under these conditions? And if I reformat and reinstall XP, isn’t there a possibility that a virus could attach itself to the new install if I haven’t eliminated it beforehand?

You’re experiencing a definite chicken-and-egg situation. You need to run an anti-virus program to possibly fix Windows, but you need to be able to run Windows in order to run the anti-virus program.

Seems like a no-win situation.

There are approaches, but they all revolve around booting something else.

When things are this broken, I often suggest just reinstalling Windows. If you do reformat and reinstall, you’ll be erasing everything – including any viruses. If you rebuild the system in the correct order, you can stay safe from the beginning and be virus-free.

The problem is that this erases everything, including all your programs and data. If you’ve backed up properly, as you should, this shouldn’t cause you too much grief. On the other hand, if you’re like too many people, losing all that data may be a real problem.

So we’ll look at a couple of options that don’t involve a complete reformat.

Since you don’t have install media for your anti-virus programs, you might consider purchasing one. Some may actually allow you to boot from their install media, and run an anti-virus scan right then and there. (Be sure to check before you purchase – I’m relatively certain this is uncommon feature.

Another approach is to download (on another computer, of course) and burn to CD a stand-alone bootable operating system.

If you’re technically adept, you can make your own bootable version of Windows using something called BartPE. Since Windows is not free you can’t just download a copy – any copy – from the Internet, legally. BartPE (Bart Preinstalled Environment) is a toolkit that allows you to create a bootable CD using the copy of the Windows CD you already own.

Many distributions of Linux, on the other hand, are free. Hence, another approach is to use one of the Linux “Live CDs”. These are free, downloadable images that can be burned to CD. You can then boot from the CD and have a running version of Linux without having to make any changes to your system or hard disk. You can then run anti-virus software against the Windows installation on your hard disk.

The most popular Linux Live CD is Knoppix. This article from “Knoppix Hacks” describes using Knoppix to perform a Virus Scan.

Another promising Live CD is Ubuntu. Ubuntu’s Live CD doubles as its install CD, should you ever want to switch.

The great thing about all of these bootable CDs is that once you do boot, even if you can’t perform he virus scan, you can still examine your Windows hard disk and possibly repair problems by hand, or at least recover files before taking more drastic action.

Since I tend to be a computer geek, I have copies of both Knoppix and Ubuntu lying around. If you don’t have an Anti-Virus program that you can boot from, my recommendation for most is to create or have someone help create a BartPE bootable disk, and then download or use the Anti-Virus software you’re already familiar with.

There’s one more approach that’s worth looking into, and that’s a repair install of Windows. You perform a repair install by booting from your Windows installation CD and selecting repair install when asked. The good news is that it doesn’t erase everything, and may get you back to a point where you can boot your machine normally. The bad news is that it doesn’t erase everything, so the viruses or spyware that got you to this point may still be lingering about. The approach to take is to use the repair install to get a bootable version of Windows, and then immediately run your anti-virus and anti-spyware scans. Possibly more than once.

Of course if the problem remains, you’ll need to look into the other approaches already discussed.

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[tags]spyware,ubuntu,knoppix,bartpe,virus scan,cannot boot,scan without windows[/tags]