I have a Latitude C840 laptop with Windows 2000. About a week ago it began "stuttering:" the mouse cursor, audio, and video hesitated for a split second, at regular intervals of about 2 seconds. It was incredibly frustrating.

The Task Manager window couldn't clearly tell me what process was stopping the machine like this, but the CPU usage meter confirmed the problem, showing regular spikes alternating between 0% and 70% every 2 seconds or so!

After lots of web searches, I went after the usual suspects. I always use anti-virus and firewall software. But this time I ran anti-virus and anti-spyware software several times in normal and safe modes. I checked the Windows 2000 boot log for strange executables and drivers. These attempts turned up nothing.

Then I uninstalled and reinstalled several drivers specific to my laptop, including power management, modem drivers, and video drivers. But the stuttering continued.

Days later, while making changes to my new wireless router by a direct ethernet connection to the router, the stuttering stopped completely!

It turns out that my old setting for ethernet connection, in the Network & Dialup Connections window, was still enabled even when connecting with my new wireless card. This ethernet setting was configured to connect "automatically" (by DHCP?).

I'm guessing that something deep in the Windows system was constantly attempting to connect with the ethernet settings, causing the stutter. This problem can only be described as a bug in Windows 2000; it allows Windows to hog considerable CPU time indefinitely when it fails to connect.

Solving the problem was as simple as slapping my forehead then disabling the ethernet setting when connecting with my wireless card. I will always make sure that my ethernet setting is only enabled when I am connected by ethernet.

I hope this helps.

Marc.