Window.dll is a system file (DLLL) that can be used by the operating system itself, as well as by games and programs. Usually, Window.dll is needed to run games (Postal 2, Lineage, etc.). There may be a lot of reasons why the file is missing, but we won't stop at them, but rather talk about how to return the file to the system. The solution to the problem may be to install one of these packages (or all of them at once): Microsoft Visual C++, DirectX and Microsoft .NET Framework.
You can also try to install this file manually. After downloading the archive with the file, use the instruction in the additional text file to install Window.dll correctly.
If none of the methods helps to start the game (or program), reinstall the game itself by downloading it from another source. Also make sure that the game supports your operating system. A good idea in this case is to install the latest updates for Windows. If you used, say, a 32-bit version of a game or a program, you can solve the problem by installing the 64-bit version (if the operating system is 64-bit).
For reference:DLL-library contains a part of the typical functionality that other programs address. The program accesses the DLL and uses the procedures and functions contained in it. In turn, the DLLL library may contact other DLLs for the same purpose. For example, Window.dll is dependent on 7 more standard WinAPI DLLs (no need to look for them, they are in your system).