I have problems with the Reactor Widget. It doesn't show a real temperature
The Reactor widget requires support from ACPI. ACPI is far from complete on many machines, and one of the more common deficiencies is that the Reactor widget can't get the temperature.
I assume that you have ACPI running, so you should be able to use the Thermal.exe program to see if it works, or not.
I uploaded a new version
I ran it for a couple of hours, with no hang, but it was very slow, and jerky, when I tried idlehlt-th.exe. It was also running all four processors at 99%. idlehlt-af.exe works much better (so far), and the processors are staying at about 5% usage. Since this machine doesn't work with the Reactor widget, it is difficult to tell, for sure, that it runs cooler, but my impression is that it does.