Windows Vista CPU usage 100 percent

by Dev Duff on October 7, 2009

Windows Vista CPU usage 100 percent

Yesterday I was working on my Windows Vista Notebook (Sony VAIO) and all of a sudden it hung up on me. I thought, Big Deal! Lets do the ole ctrl+alt+del and everything will be ok. But hay, it froze up everything. I checked task manager and found the Windows Vista CPU usage 100 percent and I was like, oh what in the world is going wrong? I calmed myself down and thought, lets take a break and let the computer sort out whatever it is doing. The HDD light was going nuts. I unplugged the internet cable from the back of notebook and left the computer.

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I think I spent around 30 minutes and returned back to see if it was done hogging the CPU but to my surprise, it was still doing the same crap it was doing 30 minutes ago. Now this time it got on my nerves and I couldn’t stop myself from hard booting the computer. Restarted the notebook and what in the world, it took over 30 minutes to reach desktop and the CPU usage was still at 100 percent. Since I have been a computer troubleshooter for over 5 years, I thought I was done with the Hard Drive or there is some virus/spyware causing the situation.

All right, I thought lets once again hard boot the computer and restart it in Safe Mode. This time, to my surprise, the computer was running like a horse in safe mode. Now this is something unusual. The computer was working perfectly OK in safe mode. Well, I guess it was about time for some fine tuning and tweaking the performance options on my computer. I started with first of all cleaning the startup programs:

Start > Run > msconfig (enter).

To be on safe side, I disabled ALL. So now there is nothing going to load up when the computer starts. Then I thought, I should give a look in the registry if there is anything funny going on in the RUN and RUNOnce folders:

HKEY_Current_User > Software > Microsoft > Windows > CurrentVersion > Run
HKEY_Current_User > Software > Microsoft > Windows > CurrentVersion > RunOnce

HKEY_Local_Machine > Software > Microsoft > Windows > CurrentVersion > Run
HKEY_Local_Machine > Software > Microsoft > Windows > CurrentVersion > RunOnce

Regedit RunOnce

There was nothing, no programs showing up on right side, no links to viruses or spyware files. Then I thought, may be there is something else that is causing the problem. I thought, lets run a full virus scan. I have the free Comodo Internet Security on my system. I ran a full system scan in safe mode. The scan took over 2 hours and the result: No Viruses Found.

Not sure if I should say I was happy to know but the mystery of computer running slow wasn’t solved yet. Then I thought, let’s get rid of some of those so called Vista Aero Effects. May be that is causing the Vista CPU usage 100 percent and fine tuned the options to give maximum performance:

Control Panel > Performance Information and Tools > Adjust Visual Effects > Adjust for Best Performance
(Please select Classic View in Control Panel if you can’t find these options).

I also got rid of some of the programs that Vista installs like Games, Search options, Indexing options and Scheduled Defrag. Those are just nothing but a pain in the rear department.

Alright, I know, that will kill the visual effects totally and I will see a Windows 98 style computer, but hay, that is ABSOLUTELY fine. I don’t understand what Microsoft was thinking while designing Windows Vista. It is such a hogger that even with 4 GB of RAM and readyboost available, my computer is slow. Come on, don’t tell me that I have heaps of software installed on my computer. Nope, I don’t. I am very choosy about installing software and I stay far away from crapware. In any case, I thought, lets give a look in the Programs and Features to see what programs I have on my computer.

I found a couple of programs that I am not using any more, I thought, lets get rid of them. I uninstalled the programs by going to Control Panel > Programs and Features.

Then I thought to run the defrag option manually. I ran the defrag on both drives C: and D:
(You may have only one partition, so run it only on C: Drive)
Start > Run > cmd. [Enter]
On command prompt window, type “defrag c:” and then hit enter (type it without the commas).
Do same if you have more than one drive .. defrag d: [Enter]

Now I was a little satisfied thinking I had tweaked and fine tuned the computer and it should work better. At least, I should not see the Vista CPU usage 100 percent and wont have any troubles reaching the desktop. So, I closed all programs and windows and restarted the computer in normal mode.

Seemed like the computer was on a mission to invade the world. It took over 30 minutes to boot everything again. Once again, the Vista CPU usage was showing 100 percent and the graph line was hitting the top. I thought may be there is something more I need to do. This time I thought to remove my antivirus and then see if I could get it going. Restarted (hard boot) the computer and started in safe mode.

This time, I uninstalled the whole internet security package. Gone! Restarted the computer in normal mode and BINGO! The computer started and reached desktop within 3 minutes. CPU usage percentage: 5%

So the culprit was the Internet Security software that was causing an overload for some reason and the CPU was going nuts. I still don’t understand why in the world I trusted a free internet security software for my computer. Alright, I learn a lesson:

Do not trust a free antivirus software or free internet security software!

Yes, that is absolutely true. There is nothing free in this world, everything drills down to business at the end of the day. If someone is offering something for free, either they are trying to sell something different while offering free products or there is some other catch. Lets face it, if you are providing something for free, you wouldn’t work too hard on it. Instead, you will work harder on things you are trying to SELL and making money out of it.

Anyway, I have learn my lesson well. Now I am looking for a good Internet Security software that can keep my computer safe from virus, spyware and hackers. Don’t want anything that eats up my computer resources and show Windows Vista CPU usage 100 percent or create any other similar situations that waste my time.

I am researching on different antivirus software and internet security software for Vista that don’t eat up too many system resources. Aero is enough to eat system resources alone, don’t want another software partying out on my system resources. If you guys have any suggestions for best antivirus software for Vista or internet security software for Vista then please share your experience and suggestions below. As soon as I am able to find a good security software for Vista, I will write another post to share my findings.

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{ 9 comments… read them below or add one }


I’m trying to tweak a vista laptop from my friend as well… How about AVG free?


Dev Duff

Ever thought why is it free? Is the company earning anything from the Free version? Think ..
On the other hand, AVG is not the best antivirus, not in my opinion. You can check this site for top ten antivirus and right now, BitDefender antivirus (or Internet Security) is on 30% discount, you can find BitDefender June Coupons here.



I enjoyed reading your story. Thank you for sharing :D



Okay, so has anyone ever heard of ubuntu maybe? Takes care of the viruses and of the statement that nothing is free. Really, give it a shot, you will laugh at your vista. Eg. I’m here because something’s wrong with me vista. This is, I kid you not, the first time since i tried ubuntu that i am back at windows, and man, am I glad I have another OS.



Lol Great story, as we speak I am in the same dilemma on a Vista machine. It was on XP doing the samething I thought ok wipe it clean install Vista which I have done but problem is still outstanding. I will later try removing AVG see if that has anything to do with it.



my vista is running at 20% with norton



avg has to be the worst for it because i hae 4gb ram on my desktop computer with avg free and it runs from 80 to 100 percent lagging all the time and i have a 3gb ram desktop comp with paid for norton and its 15 percent at peek times!



to reduce the cpu usage simply press ctrl+alt+delete then task manager then click processes see which proceess is using up a lot of cpu click on that process and end process simple as that same thing happens to me i just got a programe called gamebooster wich wen activated it will automaticaly shud down all unneccesary programmes that are using cpu for no reason and it will get ur computer running smooth trust me try it usin for years and my comp dont lagg any more



Enjoy reading the story. Me facing the same issue since last 1 week and tried with various options, i just given up and don’t have more patients to do anymore R&D.

AS you told my final option is to uninstall the Anti-Virus from my machine… Hope this will reduce my CPU usage 100 percent.


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