A friend's Windows XP laptop has become extremely unresponsive over the last few days, taking over 30 seconds to open My Computer for example and a over a minute to open a locally stored Word document. I assumed that a process was consuming all the CPU but on looking in Task Manager, the CPU hovers around 10% while loading MS Word or performing other tasks.

Any ideas???

It's a fairly old computer - 2GHz P4 with 256Mb RAM but has been reasonably usable up to now.

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    What was changed before the problem occurred? Was any new software installed?
    – Tester101
    Oct 5, 2009 at 15:43
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    It turns out that Microsoft Security Essentials was installed a couple of days ago. I've just checked the system requirements which say a minimum of 1Gb of RAM. Will get him to install Avira instead and see if that fixes the problem.
    – pelms
    Oct 5, 2009 at 16:31
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    just out of curiousity: 1 GHz? AFIK, the slowest Willamette was clocked at 1.4 GHz.
    – Molly7244
    Oct 6, 2009 at 10:38
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    I had the same problem when I installed Microsoft Security Essentials. Something was accessing the hard drive constantly (I mean the light never turned off), I disabled automatic updates and the problem stopped. I promptly uninstalled Security Essentials, and placed it in the crappy software category.
    – Tester101
    Oct 7, 2009 at 19:20
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    @Molly. You're right, it was a 2GH P4.
    – pelms
    Oct 10, 2009 at 19:12

6 Answers 6


That could be caused by disk activity. Eventually the disk is getting bad, and the OS needs several retries to retrieve data from the disk.

Install a software that does SMART reporting (search for the SMART tag on superuser for several tools) and check if the disk reports anything bad.

Maybe 256 Mb RAM is not enough and the system is swapping a lot. Check with Process Explorer the I/O activity.


Keep in mind that CPU usage by default doesn't show CPU used by the kernel. Select show kernel usage in the view menu of task manager.

However you could always try Process Monitor, which was a program written years ago and them bought by Microsoft. It's essentially a lightweight replacement for Task Manager, but it shows a LOT more detail.


Heavy Internet access can also freeze the machine, such as some program desperately trying to call home to a non-existent web address.

Use TCPView for Windows to see which programs are connected to tcp/ip ports when the freeze arrives.


Six years later...

This can be caused by overheating.

  • Laptops tend to collect dust over time, which clogs their airways, their tiny fan, and the fins of the CPU heat sink. Also,

  • The heat-conducting paste between the CPU and its heat sink tends to deteriorate over time, (especially if the CPU is subjected to extreme heat a few times,) and the result is, again, insufficient extraction of heat from the CPU.

These conditions cause the CPU to heat up to extreme temperatures.

Now, every modern CPU has heat sensors and associated circuitry which causes the CPU to throttle down its clock in order to avoid burning the chip. You see, modern digital electronics only consume power during clock transitions, so the lower the frequency of the clock, the less frequently it transitions, so, the less power is consumed.

(Incidentally, a lower clock rate can also accommodate a lower voltage for even greater power savings, and this is a common power-saving strategy in modern systems, but I think that when the CPU self-throttles its clock the voltage is not reduced, because the voltage regulation is done by the motherboard, which is blissfully unaware of the stress that the CPU is undergoing.)

Anyhow, the apparent effect of this throttling down of the CPU clock is extremely slow performance. It is like having a CPU which executes a few instructions, (clock cycles,) heats up, stops executing anything, waits to cool down, and then proceeds to execute a few more instructions, all in a cycle of less than a millisecond. You see, the CPU die is a very small piece of metal and silicon, so it has a very small thermal capacity, so it heats up very fast, and it also cools down very fast.

In order to determine whether overheating is actually your problem, you need to obtain some program which measures the CPU temperature over time, and see where it stands. Generally, the 60°C/140°F ballpark is okay, while the 80°C/180°F ballpark is too hot, although the specifics of your system may differ.

If overheating is your problem, the first and easiest thing to try is to have the airways of the laptop cleaned from dust. This might work, but there is a considerable chance that it won't work, because your laptop has already been subjected to extreme heat, so the heat-conducting paste may have been damaged. So, if cleaning the airways does not work, then the next thing to try is to have the heat-conducting paste replaced. And since this is a laptop, this should only be done by a qualified professional.

I am not a qualified professional, but I have replaced the heat-conducting paste on two different desktop computers which were exhibiting very poor performance for no apparent reason, and lo and behold, the problem was completely fixed in both cases.

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    Open Hardware Monitor is "free open source software that monitors temperature sensors, fan speeds, voltages, load and clock speeds of a computer" that could be used. The software runs on 32-bit and 64-bit Microsoft Windows XP / Vista / 7 and any x86 based Linux operating systems without installation.
    – moonpoint
    Jul 26, 2015 at 14:01
  • Thanks for the info Mike. I can't recall what happened with that laptop now, probably belonged to a relative. I'm on a mission to get all my relatives on to Chromebooks to avoid having to supports them through regular malware infections and the like :¬)
    – pelms
    Jul 29, 2015 at 12:23
  • Yes, I mostly posted this for the sake of the future generations.
    – Mike Nakis
    Jul 29, 2015 at 12:40

This is often caused by a virus. Check the machine.


If the CPU usage is "normal" then windows OS is waiting and timing out for something.
* It can be an earlier mapped drive, which is no longer available, OR
* an unavailable printer or locating available printer (Does it also take time to open cmd window ?).
* It could be that the driver mapping itself is taking time.
* Following link talks about searching for scheduled tasks on mapped drives. http://www.computing.net/answers/networking/slow-my-computer/5586.html

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