Just had a bad experience and felt the need to express myself.
I purchased a copy of HMonitor
http://www.hmonitor.com/ a while back.
It is a key based system (which is fair enough) but be warned if you buy this software.
If at some future date you need to reinstall Windows the key will not work and if a new version is released the author will not supply a new code unless you buy the version upgrade. I have not changed my hardware so I do not need an upgrade, or gain anything if I do.
This would be fair enough if I upgrade my hardware and need the later version for support but I don't !!
To my mind this is the worst of practices (and pretty unique in my experience).
Effectively you are held hostage to upgrades.
If you want a hardware monitor I would suggest looking elsewhere !