.NET allows assemblies to specify the name AND the version of any assemblies they need to run.

Dll hell, is kind of conflict that occurred previously, due to the lack of version supportability of dll for (within) an application .NET Framework provides operating system with a global assembly cache. This cache is a repository for all the .net components that are shared globally on a particular machine. When a .net component installed onto the machine, the global assembly cache looks at its version, its public key and its language information and creates a strong name for the component. The component is then registered in the repository and indexed by its strong name, so there is no confusion between the different versions of same component, or DLL