Definition - What does DLL Hell mean?
Techopedia explains DLL Hell
In more current versions of Windows, some of the problems that contribute to DLL hell have been addressed and solved to some extent. Changes include a .NET framework, which uses metadata to describe program components. This system helps with versioning and deployment to alleviate some of the problems that arise due to cross-language DLL use or situations where applications have to share a DLL file. A Windows File Protection system, introduced in Windows 2000, stops some programs from changing system DLL files. Other solutions involve placing an application's DLL file into a separate folder rather than storing it in a shared location so that each application can have its own unique version of the DLL file.