Don't Sleep

Don't Sleep is a tiny but powerful application that prevents your computer from shutting down or initiating any other power-related action.
This program doesn't require any installation, so that means it is portable. In other words, your Windows registry entries will remain unchanged, but you can also place the tool on an external device and run it on any other computer.
The user interface of Don't Sleep consists of a small window in which you can select your "blocking" preference - standby, hybrid standby or hibernation, block shutdown, log off, screensaver or turn off monitor.
Furthermore, you can schedule a "blocking" task at a specific date and time, as well as select the action - exit and stop blocking, exit and shutdown, exit and aggressive shutdown, exit and standby or hibernation, disable blocking.
In addition, you can set a screensaver timeout, as well as a time for the application to start running. Plus, you can access some Windows utilities such as 'Task Manager' and 'Power Config'.
Don't Sleep uses a very low amount of system resources. Although it is simple to use even by individuals who are not accustomed to this type of program, there is no help file available (for instance, to explain the difference between 'shutdown' and 'aggressive shutdown').
All in all, Don't Sleep provides a great solution for when the computer automatically restarts or enters an idle state. We strongly recommend it.