Are you looking for the Random Error Checker? I removed the link from the navigation bar because I have been planning to develop a better one. Expect to see the new version sometime this spring. In the meantime, try this random error checker. Embed it on on your blog or Moodle course page using iframe code in HTML mode.
There is a limit to what a online grammar checking website can do. If you want more help with your writing, I can recommend an editing/translation service that is surprisingly affordable. Clicking on the link will take you to In the Box. For a discount, mention that you were referred by the Virtual Writing Tutor. Ask for a discount now.
If you want a more advanced level of automated feedback on your writing, I definitely recommend Grammarly. Click on the banner below to get the Virtual Writing Tutor's special discounted price for Grammarly.