YKill - Version 1.1 YKill gives you information about all top-level windows that are running in the background. With YKill, you can close and kill windows instantly and if you're not sure which window is the problem, you can scan all tracked windows in search for the stuck ("Frozen") window. YKill can also help you in case of emergency: With YKill, you can run applications and shutdown your system directly from the menu. You can also choose which windows will be tracked, using a predefined a style or your own custom style.