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Slow computer after an install? This feels like either malware or the beginnings of a flaky drive.

I have a 5/2 yr old Dell desktop, 2.4 GHz, 250 GB hard drive, running Vista Home (Premium, I think). Lately it's been getting slower so I finally backed it up multiple ways and reinstalled Vista from the recovery partition. That process reformatted the hard drive (supposedly) and installed Vista Home. Unbelievably the system is now running slower than before. Everything is slower: boot up, email, Windows Mail, web apps. I've reinstalled the last 5/2 years of Windows updates. I've not put all my photos back on, so instead of being 90% full it's now 40% full. I had MS Security Essentials but removed that and put AVG free on; just trying something different. No soap. Still very slow. The AVs and Malwarebytes all say the system is clean. Does a reinstall from a recovery partition not really wipe everything clean? Should I boot a DOS disc and repartition and reformat manually? This would blow away the recovery partition but at this point, I don't really care. Any light you can shed on the situation would be very much appreciated.

In this excerpt from Answercast #69, I look at a case where reinstalling the operating system has slowed down a computer even more than before!

Slow after reinstalling

There are two things that come to mind for me - neither of which are particularly easy to deal with, but they are the things that come to mind.

Continuing malware infection

It is conceivable that malware survives a reformat like this. If malware manages to infect your recovery partition, which I believe has been known to happen, then a reformat and reinstall from the recovery partition may in fact still propagate the malware on to your new machine. It's conceivable that the malware itself is running and slowing down your system.

One thing I would do, of course, would be to run Process Explorer to see if there's anything untoward running on your machine that you're not expecting, or something that's eating up lots of CPU, or something that's doing a lot of disk I/O that you're not expecting.

Bad sector on hard drive

The other thing that comes to mind, that I think more closely matches the symptoms that you've described (in other words, getting slower after this reformat) is that you have a marginally bad sector on the hard drive.

In other words, the sector is either bad or going bad, but it's not so bad that it can't be read. It's bad in that it takes the disk drive several tries to read it every time it needs to read it. So, the first time might not work, the second time might not work, the third time it finally gets it right. I'm thinking one-two-three, but given the speed of computers, it could be the first hundred times it tries to read that sector it fails, but the 101st time it succeeds.

It's unclear. It's hard to say exactly what specifically is going on at that level, but it is one possible cause for a system slow down.

Why would it be slower now than before?

Well, by reinstalling the operating system, you've put things back on the hard drive in essentially a different place. So, if that bad sector used to contain say a directory entry for a directory that you accessed infrequently, then you would experience a slow down only when that particular directory entry was being accessed.

On the other hand, if now with the reinstall, that sector contains something important... something that the operating system is reading frequently, maybe it's in the paging file, maybe it's in an operating system core file, it's hard to say. But if the operating system is now having to read it constantly or frequently (and this slow down that I'm talking about, where the sector itself is not being able to be read reliably), then that would magnify the impact of that bad sector on the overall speed of your system.

Repair or replace the disk

Now, solutions: there are two that I can think of.

One is this is exactly the kind of scenario that a utility called Spin Rite is designed to solve. It will actually go through and refresh that sector. It will test the heck out of it. If that sector's not going to work, it will mark it as being bad and move the data around so that it's no longer being used - and the bad sectors then no longer impact your performance.

The other solution... because Spin Rite is $95 and $95 can probably buy you a pretty good hard drive. The other solution would be to back up your entire hard drive, replace the hard drive, and then restore that new replacement hard drive from your backup image.

Those are the two different kinds of approaches I would take. I happen to have Spin Rite already for many different reasons. So, you know, obviously then, already having paid my $95, I'd absolutely go to Spin Rite right away. Let it work on the drive and see if that doesn't resolve the problem. But not having Spin Rite? Sure, it makes sense that maybe replacing the drive would be the thing to do in a case like this.

So there's two options... either malware or the beginnings of a flaky drive.

The malware is something that you can run additional tests on. It's something that you can go out and do. I would absolutely make sure that you run your anti-malware tools against not only the installed system but the recovery partition.

I would actually go so far as to look for some good rootkit tools because it's rootkits that often can survive a little bit longer than some of the other types of malware.

One way to absolutely get rid of the malware is as you described: reinstall the system from scratch for real - not using the recovery partition. I don't think you have to get a boot disc or a DOS disc. I think you can get yourself a Windows installation disc. You'll be able to boot from that. That will then allow you to manipulate the partitions, potentially delete the recovery partition, reformat the hard drive, and install Windows from scratch - in that case, installing only the bits that were coming from the installation media itself.

That would be another safe way to make sure you're avoiding malware as being the cause of this.

If on the other hand you do all that, you still end up with a slow hard drive? Then I'd be really, really tempted to replace the hard drive and see if that doesn't resolve the issue for you.

Article C6021 - November 12, 2012 « »

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?

November 13, 2012 8:42 AM

Lemonade from lemons solution: get a new, larger, faster hard drive, and install Windows 7, which is also faster than Vista. Upgrade RAM while you're at it. This will give you a faster system with enough room for all your photos and more. Also might compare the cost of all that with the cost of a whole new system.

Robert Dufresne
November 13, 2012 3:32 PM

A slow computer can be the result of dust gathering in the CPU heat sink, thus allowing heat to build up and slow down the CPU. I have run into this on both desktops and laptops and I recommend cleaning the heat sinks.

Gary Richtmeyer
November 13, 2012 3:34 PM

As a PC tech, I've heard these symptoms many times, and almost always the HD is failing. Leo's recommendation to simply replace the HD is right on. (We have SpinRite too, but with the low cost of today's HDs, it's simpler, faster and cheaper to just replace the HD.)

It's possible that Windows has some infections that survived the re-install (bootkits/rootkits for example), but the odds are low. Plus, a slowdown wouldn't be immediately apparent, it would appear gradually over time.

Vanya M.
November 13, 2012 4:52 PM

I would go with Leo's "suspicions" about dying Hard disk...

Just another stated that over years you've been updating Windows regulary...
If you didn't update all those "updates" now, again, after reinstall, that could be the reason, cause, 5 1/2 years is looong time for comp, especially in sense of software recomendation for hardware force... Those problems are partly solved through Win updates, but now, if you ate trying to run 5 years newer apps on such an old version of Windows, you could be finding part of your trouble there...
And, at the end, I have to agree - lose Vista, go for WIN7 and some extra RAM - i would suggest it any way - with or without the problem you are facing...
Hope you'll get it solved!!!'

November 14, 2012 5:41 AM

Try some additional troubleshooting.

(1) Reset BIOS back to default settings. {to access, press either F2 or delete{del} several times as computer boots up.

(2) Pull out ide or sata connections{both ends} from hard drive & DVD drive to motherboard then plug back in. Oxidation can cause a film build up over time.

(3) Take out ram & replace in different slots. Contacts can be cleaned with an eraser.Earth yourself first or wear latex gloves. Static electricity can damage ram contacts

(4) Disconnect peripherals such as printers and ipods including internet connection.Disconnect mouse and keyboard and reconnect to another USB port.


A Richter
November 14, 2012 10:38 AM

To test HDD for possible failings on the cheap, why not download the Ubuntu ISO, burn it to DVD, and run it live on the system. It has a nifty disk checking facility; if any bad sectors are detected, it would be a clear signal for replacing HDD indeed.

November 15, 2012 4:25 AM

(1) Run the Windows utility called chkdsk .This utility can find bad sectors & often fix them. Google for procedure.

(2) Go to your hard drive manufacturers web site. Most provide a free download program to check for faulty hard drives. Some applications require burning to CD and booting from the CD. BIOS must be set to boot from CD first if this is the case.

Dave Markley
November 15, 2012 11:11 AM

I agree with Leo and the others that your hard drive may be going bad, BUT, there is a couple of things to try first in my opinion. And all of them FREE!
First, everything you installed, Microsoft files especially, need to be 'cleaned up after'. Download CCleaner and run both 'Cleaner', then 'registry' options (from tabs on the left)., Then go to the 'tools' tab and choose
'Startup'. Anything not immediately necessary for your PC and anti-virus to run should be 'disabled'.
Next, open 'computer' and right-click on drive 'C'. Choose 'Properties' at the bottom. When the box opens choose 'Tools' and then 'Error-checking'. Click 'Check Now'. Make sure BOTH of the boxes are checked. Your PC must restart for this to start running and it may take several hours. Just restart the computer and let this run. It's best to do this before you go to bed, when you get up it should be done.
And finally, if you haven't done so already, defragment your hard drive. I personally prefer 'Ultra-Disk Defrag' (also free) set on 'Full Optimization.

I've seen many hard drives replaced that could probably have been saved with these simple tricks. Good Luck!

November 15, 2012 3:30 PM

As Dave M suggested, too many start up programs often lead to slow response.

I have often found that it is the Anti Virus program that is causing the problem.

I always disable anti virus when trouble shooting. You can disconnect from the internet if concerned about infections ..

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