Missing msvcrt.dll file in Win98

I recently installed some older software which has overwritten my newer msvcrt.dll file with an older one. It is affecting my email as well as my Norton SystemWorks 2003(which means I have no virus scan at the moment). I have uninstalled Norton & reinstalled it, I’ve tried through Dos to copy the newer file back into the system, but access is denied? I’ve tried through sfc to extract the file and reinstall it, but no luck! HELP!!