Body field is not displayed in Comment Views
Well.. at this point you may have to resort to the following.

First of all, make a backup of your database. 

Plan A) Disable views and uninstall it (so all the database tables are erased), then delete the views folder. Download it again, upload the folder and enable it. If this fixes your problem, you can use the view's export/import to quickly import all the view's you had.

Plan B) Disable every module you have in sites/all/modules folder except for Views. Then if it works now, enable them one by one to see which one is causing this. 

Plan C) If A or B doesn't work, well... I hate to say it, reinstall Drupal :(