Why are SYSTEM and taskmgr.exe taking up 100% of my CPU?

I'm running 32-bit Windows 2003 R2 in VMware 6.0.3 on my Windows XP 32-bit host OS. I have run all the Windows updates, but haven't done any other tweaking. About once every hour (but not quite on a schedule) my CPU usage goes to 100%, slowing everything down for about 1 minute. When I can get taskmgr up, I see that usually a process called "SYSTEM" is using most of the CPU. Occasionally taskmgr itself is using up almost all of it. What is causing this, and how can I avoid it?

The host machine is an older Pentium D with 3 gigs RAM. The VM is running from a relatively fast SATA drive. Memory usage in either the host or the guest doesn't seem to be a factor in whether or not these slowdowns will occur.

thanks! Chris

From stackoverflow Chris Farmer

• I happened to stumble across the same problem you are describing, one of the processes of vista itself that uses all, or most, of the CPU resources for a few seconds to return to normal afterward, and back again. It wasn't my own computer so at first I hadn't a clue of what was installed recently, if the problem did occur before but was never noticed etc, so I had to go look and see if others might have the same problem

  As it turned out it was a misbehaving driver of one hardware components that caused the problem, unfortunately the driver wasn't updated yet so I couldn't fix the problem entirely, (disabling did help though)...

  However you are using VMware thus a driver issue is, i think, rather unlikely. of course you never know.

  Great Turtle : I'll second that. Drivers run as the OS level. Lately they are getting worse and worse. Especially the cheap knock off hardware with unsigned drivers.
  From Sven
• I don't know if there is a similar app on XP that the "Performance Monitor" on Vista, but it could be very useful to find wich particular process/service is causing trouble. It is also very easy to see what process use your hard disk or the network... I think your problem is more specific to VMware... I'm having an issue on my Dell XPS M1330 with VMware server on Vista : first launch => 5 min freeze !! (lot of swapping, pagefile is full, ...) others have the same problem.
  From TiTi

• It might be a Windows Update service - I've stumbled at it several times, but only when the host didn't have CPU VT capability. I'm not sure whether your Pentium D supports Intel VT, old Pentium D's do not.
  Try turning off automatic updates and see if it helps.

  As a workaround, try granting the virtual machine two CPUs. One will still be hanged by outlawed SYSTEM process, but second CPU will handle everything else just fine.

  From $pageUsers[$post.author].name