Running Win7 Home Premium and Firefox 37.0.1. Since this upgrade, when any of my three computers goes to sleep, Firefox stops working. Sometimes the process can be exited, but regardless, Firefox cannot be reloaded and the computer must be rebooted. When the computer has gone to sleep, and Firefox has stopped working, other browsers, such as Explorer also say they cannot connect to the internet. The fact that this problem simultaneously appeared on different computers following this upgrade suggests that this is a Firefox problem. The only way I can avoid this is to exit Firefox after every use. In many cases, the only web page visited during a session is google.