The NLS prefix indicates that is part of the OS' national language set files and, most probably, not needed by your installation (English language, presumably). If the Stinger runs clean, I wouldn't rush to reinstall the OS, rather, go on-line (or have someone copy theirs for you) and obtain a copy of the .dll files, or rename the extensions and run the PC and observe its behaviour. Only then should you consider reinstalling the OS. Now, if you want practice, a clean OS and a faster PC (if you install only the minimum for your needs), go for it.