Using a registry cleaner is also recommended. A registry cleaner will scan through the "registry database" and fix any of the damaged or corrupt settings inside your PC. The registry holds all the settings for your computer, and crucially, it's home to a large list of DLL file references that Windows uses to help programs load the files they need whenever they need them. It's often the case that this DLL file list gets damaged, causing Windows to become unable to read the files it needs... causing all sorts of errors. This is one of the main causes of the mfc80u.dll error and can be fixed pretty easily with a registry cleaner.glaszetter