Luckily WordPress 2.0 allows WYSIWYG visual editor to be turned off or disabled. However, when wants to enable and use WYSIWYG visual editor again, the visual editor simply doesn’t appear nor show up. It’s as if visual editor has vanished into the thin air. The situation might happens even if you never disable the visual editor before.
The most likely cause of the problem is because in WordPress 2.0, there are 2 places or options that you can disable the visual editor. The first option is, of course, at Options -> Writing, under the Formatting title, users can select or unselect Users should use the visual rich editor by default to enable or disable visual editor.
However, there is another option at Users Personal Options, where users can select or unselect Use the visual rich editor when writing to enable or disable visual rich editor for each for each user individually. The setting here has higher priority that the setting at Options, which may simply set the default option when new user is created.
So when your visual rich editor is not working properly, check the Personal Options at Users to see if the “Use the visual rich editor when writing” is checked.
And it’s the same if you want to disable WYSIWYG visual rich editor. Just make sure the option at Users Personal Options is unchecked to get rid of it.