For a while I have been suffering that when I switch on my Acer Core2 Duo Vista laptop, both cores sometimes go to 85%+ utilization, so the PC is slooooow. Usually after a few reboots it seems to clear. This can happen after a resume from hibernate and complete restart; there was no obvious pattern. Task manager only says that the load is due to the NT Kernel process – so not much help there.
After a bit of google’ing I found other people reporting the problem after installation of Microsoft Network Monitor 3.1, which I did months ago Interestingly I have only seen the problem is recent. However, as soon as I went into the network protocol stack and disabled the network monitor protocol on my WiFi card the problems have gone away.
My guess is some strange race condition caused by a recent service patch; this not a major problem as you can switch the protocol on and off as required without a reboot.