|Google is your friend|
You should try searching the following string "download wrusr.dll" and I'm willing to bet you'll find it. A little more research on something like "wrusr.dll is missing" might tell you how to fix it without downloading/installing a new file.
It matters not how straight the gate,
How charged with punishments the scroll,
I am the master of my fate;
I am the captain of my soul.