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When defragging a hard disk, some files in use by Windows can't be moved; in the defragging tool, they appear as green bars. But don't worry - they're not viruses.

My local advisor tells me I have a virus in my BIOS, which cannot be removed; at least, not by Norton. Proof of the virus, he insists, is that I have two green columns in the dialog box of my disc defragmenter. He further insists that the green will continue to expand until my PC fails completely. A second advisor insisted the second green column could be eliminated by going to Systems, Performance, Virtual Memory and clicking "No page file". I tried several times. As soon as I restore the page file, the second green column reappears. Then, he suggested Page It also failed to eliminate the second green column. At that point, his confidence failed and he too leaned to the virus as the most probable explanation. Is this a situation which should worry me? My PC is five years old and is running fine. I have Norton 360 v4 on Windows XP. My C: drive has 290 GB cap and 280 GB free space at present.

I think it's time to find new advisors.

Those green bars are normal and expected. They don't indicate a virus at all, BIOS or otherwise. And the advisor who suggested that they do is just plain wrong.

I'll show you what they do indicate.

Green Bars

To make sure that we're all talking about the same thing, here's an example of green bars in the Windows XP defragging program:

Unmovable Files in the XP Defragger

This happens to show one large bar, but, in fact, it could be several green bars or lines throughout the display.

"BIOS viruses exist, but they're very rare."

Green lines do not indicate a virus.


As the legend at the bottom of that very window tells you, the green bars indicate "Unmovable files"; nothing more, nothing less.

Unmovable Files

So, what's an unmovable file?

Well, your second advisor was at least on the right track. Unmovable files include things like the system paging or virtual memory file, the registry and other files that Windows has locked for exclusive use while it's running. If Windows has them locked, then the defragging utility can't defrag them.

Sure, removing your paging file may well make some of the green bars go away. By not having a paging file at all, there's nothing for Windows to lock. But that's rarely the correct solution. Most machines need a paging file configured to run properly.

Besides, getting rid of green bars isn't really a useful goal. As I said, they just represent a few files which the defragger can't move.

That's OK.

Page Defrag

Running Page Defrag could certainly reduce the number of green bars. It does so by defragging the paging file and other files before Windows actually runs.

Remember that defragging is all about taking the various parts of a file that might be scattered all over your hard disk and moving those parts so that they are all right next to each other. This helps speed up disk access.

Defragging the paging file might move two or more of those green bars next to each other so that they then appear as a slightly larger single green bar.

That's all.

What about a BIOS Virus?

A BIOS virus is highly unlikely.

BIOS viruses exist, but they're very rare. They're not of great value to hackers who can typically infect many more machines with much less work using a more traditional virus.

At this point, I'm afraid that I can't trust the judgment of your first advisor who seemed to think you have a virus simply because the defragger showed some unmovable files.

As I've said, they're completely unrelated.

Article C4741 - February 13, 2011 « »

Leo Leo A. Notenboom has been playing with computers since he was required to take a programming class in 1976. An 18 year career as a programmer at Microsoft soon followed. After "retiring" in 2001, Leo started Ask Leo! in 2003 as a place for answers to common computer and technical questions. More about Leo.

Not what you needed?

February 15, 2011 8:26 AM

I thought you could only get a BIOS virus if you tried to flash the BIOS with a dodgy update. Has that changed?

Yes, but as I said it's extremely rare and not something I spend time worrying about. Be sure to check out the related article listed.

Me too
February 15, 2011 8:44 AM

You need to immediately fire both of those advisers. They are clueless to the extreme

Dave Markley
February 15, 2011 9:27 AM

I hate to put someone down in public, but run far and fast from your local 'advisor'. He is either a con artist or, as Leo said, "just plain wrong"!

Those green bars ARE your Windows files! If you were to delete them your computer would not even turn on! No, Windows Disk Defragmenter is not capable of moving them, however, several 'after-market' defragmenters can.

My personal favorite is 'Defraggler' by Emsisoft (makers of CCleaner and Recuva - two excellent programs in their own right). It's 100% free and you can you can schedule it to automatically defragment all of your drives daily, weekly, however you want. It is fast and extremely efficient! It works much better, faster and efficient than Windows built-in Defragmenter.

Russ Jackson
February 15, 2011 9:52 AM

Well now, it would appear that Larry and Moe are alive and well and living as "Local Advisors" which they are as good at as they are at hanging wallpaper. Keep your eyes open for Curly, he must be around there somewhere. And try Defraggler like D.M. suggested. It just plain works.

February 15, 2011 11:18 AM

Those green lines are viruses? Nope!
I'm not one to put down somebody I personally don't know but, sheesh, send those advisors to the White House.
Seriousely, if you doesn't know, ask somebody who does. Then ask somedoby else.

I run Asulogics Disk Defrag and I like it just fine.

Bill Trail
February 15, 2011 11:53 AM

Dave Markley (above) said Defraggler comes to us from Emsisoft ? It most certainly does not.

Emsisoft is a company (and a web site) that would like to sell you on using THEIR anti virus program but PC Magazine reviewed it middle of 2010 and stated that it is easily one of the WORST anti virus programs they’ve ever tested and gave it a lowly 2 out of a possible 5.

Always do your due diligence before buying into ANY statement about a software product or company. Here is the link to that review:,2817,2364196,00.asp

Piriform has offices in London and here in the United States and Canada and their excellent and free (and paid version) software tools are at the very heart of my and many other PC virus removal and computer speed-up companies. Visit them at


Bill Trail, owner:
Penny Systems, Inc. (founded 1984, making my company older than most of you reading this)
Macon, GA

February 15, 2011

Dan Markus
February 15, 2011 5:25 PM

Why use Defraggler and not use the defrag that comes with windows

Some people swear by it, but I see no reason to get an additional tool. Yes, it may defrag "better", but if you simply keep your machine defragged regularly the incremental difference from running a better tool isn't going to be noticable.

Jon Bedford
February 15, 2011 7:07 PM

The Windows Defrag utility is a 'barebones' defragger in terms of efficiency. Much better results are possible with a number of third party products which are free. Usually these products will defrag more completely than the Windows defrag utility and will provide more information afterwards. Folks who like data will appreciate this aspect of some of the third party defrag products.

The Piriform 'Defraggler' product, mentioned above, is likely a great choice. However, I do not have personal experience with that particular program; only with Piriform's 'CCCleaner' utility which I can readily recommended for general maintenance and more. My experience is with a defragger program entitled 'MyDefrag.' This used to be known as 'JK Defragger.' I have been very pleased with the product, which is free. The reviews were good too, which was the basis of my choice at the time. The interface is a bit limited with 'MyDefrag' and may not be intuitive for some. Yet, a cursory reading of the help material will resolve elemental concerns of operation. The feature I like most is the 3 levels of operation called Daily, Weekly, and Monthly. The Monthly is best run overnight. The other two are much more quick and will complete in 5 - 15 minutes many times depending on the frequency of which you run the program. Windows has a bit to do with this as well. The 3 'routines' found in MyDefrag' each perform a different 'intensity' of de-fragmentation, per the documentation. A log file is produced which is how one reviews the defrag results. However, the log file will not be rendered upon completion. Creating a shortcut to the file found in the MyDefrag directory will make it convenient. Aside from these relatively minor issues, I find this to be a great product that will certainly blow the pants off the of defrag utility built into XP and provide defrag data afterwards sufficient for most everyone. Likely, the next question for most will be... "What is the Journal?"

You are at 'Ask Leo,' right?

Spaceman Bill
February 16, 2011 9:47 AM

I'm really glad that this article came up; it reminded me that I hadn't defragged my XP machine for a while. When I started, there were three of the "green bars", of varying widths, showing up on the display. Running it 'got the red out' but the three bars remained, unmoved and unchanged, as expected.

Just for hoots, I went into my pagefile settings and reduced the memory allocation to "0", rebooted and opened defrag again. The display was just as I left it, with the three bars showing. I re-ran defrag and this time, after it was over, there was a single green one left; it was slightly smaller than the smallest previous bar had been. After that, I reset the memory allocation to the default setting, and rebooted. I didn't notice any real performance change (my drive was 85% free to start with) but I suspect that I had freed up some usable storage space.


February 16, 2011 12:58 PM

I use Ashampoo magical defragmenter, which was free when I downloaded it although I believe it isn't anymore. Anyway it defrags in the background, so I never have to worry about my machine getting fragmented. It works.

Lee Doan
February 17, 2011 8:39 PM

I use Iobit Smart Defrag, which has a deep optimize function, that I like, to optimize plus defrag.

February 25, 2011 4:25 AM

I kept having too many problems with incomplete defrags and when I needed to defrag once under low free space, tried out the demo of Diskeeper. Upgraded soon after as it did a fab job not leavin out any fragmentation.

July 4, 2011 12:45 PM

Windows defragger is the best utility for defragmentation of local files simply because Microsoft wrote it specifically for the Windows operating system. For people who go off buying third party defrag software, don't! Yes in later versions of Windows (Vista+) the visual defrag has lost some functionality but there is a better alternative and one that has always been there, command line defrag! Open a run window and type "cmd". A dos window will appear, next type "defrag" and all the options for defragmentation will appear which include a full defragmentation for hard disks and providing a verbose analysis for pre and post defragmentation statistics.

Steven Bell

{url removed}

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