Ntrain2k:  So it works if you start mining at intensity 19, but if you start it at 14 and set it to increase to 19 during idle it locks up? If I'm understanding you correctly, it's difficult to say... CGWatcher is simply sending a command to cgminer telling it to change the intensity. It sounds like more of a cgminer issue, but since cgminer no longer supports GPUs I'd suggest looking at sgminer, which is a cgminer fork focusing on GPU mining. As I mentioned above, you can download Windows binaries here: http://coinmyne.proboards.com/thread/24/sgminer-compiled-version-download