Hmm, I don't know. It does freeze up for a few seconds sometimes on initialization for me, but always works after that. Could be having problems with your specific hardware, couldn't really say. You could try uninstalling it and reinstalling. I'm using 4.40 Beta 5, you may have success with it, but you have to register with the site to get it. And run it as administrator. SpeedFan Beta Program
And instructions for installing the beta.. In order to run this beta, simply install SpeedFan 4.38, then replace the EXE and then run SpeedFan as usual.