How about simply deleting the folder (remember backup the CodeWorksforAndroid folder which has all the downloaded data) then go to System → Advanced System Settings → Under Advanced Tab → Environment Variables → Delete all the Relevant Variables to list → PATH, NVPACK ROOT, NVPACK_NDK_VERSION, NVPACK_NDK_TOOL_VERSION, NDKROOT, JAVA_HOME, GRADLE_HOME, ANT_HOME, ANDROID_NDK_ROOT and ANDROID_HOME, Then reinstall NVPACK to custom location.