Vizio.com has a series of articles for troubleshooting Vizio television remotes. VizHDTV.com also has tips for troubleshooting a Vizio TV remote, including an article on how to fix a Vizio TV remote in five simple steps.
The first step in most Vizio TV remote guides is to make sure the remote sensor isn't blocked on the television. Power cycling the remote and television are typically the next step. This is basically removing the batteries and reinstalling them and unplugging the television and then plugging it back in to drain residual power. Making sure the batteries are installed correctly and functioning is typically the next step. Replacing the remote is the last step when nothing else seems to fix the remote's issues.