How to get notified of Windows process maximizing CPU?

Question

Is there a tool for Windows XP and Vista (built-in or otherwise ideally freeware/OSS) that can notify the user when the CPU is above a (configurable) threshold for some (configurable) duration?

I am particularly interested in a minimalist tool that fits the following bill and in order of importance (which a lot of the built-in Windows facilities like Performance/Resource Monitor do not):

1. Does not require administrative privileges
2. Has a low working set so it has no observable cost if left running forever
3. Monitors silently in the system tray
4. Uses a subtle (not in-your-face) notification method like showing a balloon tip with the name of the offending process that has been maximizing the CPU
5. Can be configured to start automatically when a user logs on interactively

Answer 1

You could write your own utility.

Here a sample as starter: http://gist.github.com/11658

1. Create a CpuMeter instance
2. ResetCounter
3. Wait for an intervall
4. Check Cpu utilisation
5. Start again