Desktop: Blank

Are you seeing blank screen only in wp-admin?
Also have a look at Common_WordPress_Errors

Yes, It is in wp-admin.

Checked out Common_WordPress_Errors. Followed directions and it seems to be there is no problem with plugins or themes.

When did this problem show up? What was the last thing you did before you notice the problem? Is this a public facing website?

Since this week. I did two things: I updated askimet (followed instructions to uninstall via ftp, but didn’t work) and added a new page for a quiz. If by public facing website, you mean a public Web site, it is. I use it to publish tasks for my students.

Have you tried disabling all plugins to see if the problems go away?

Yes, I did. Following the instructions from Common_WordPress_Errors. Nothing happened.

I think your site have some parse or fatal errors but it doesn’t showed up. Have you tried to enable the debug mode in wp-config.php file?

Turn on the debug like this:
define('WP_DEBUG', true);

That seems to be coding or something…Should I copy-paste this define(‘WP_DEBUG’, true); in the wp-config.php file?

Should I paste this define('WP_DEBUG', true); anywhere? at the end of the wp-config.php file?

That code is already in the wp-config.php file.
That’s around line #81.

Just change it from:
define('WP_DEBUG', false);

To:
define('WP_DEBUG', true);

This way we can check if your site has fatal errors.

OK. I found in line #81 this: define(‘WP_DEBUG’, false);. I will change this for define('WP_DEBUG', true);?

Yes

OK. I got this message:

Notice: Undefined index: page in /home/miguelme/public_html/wp-content/plugins/wordpress-notification-bar/inc/class-plugin.php on line 126

Notice: Undefined index: page in /home/miguelme/public_html/wp-content/plugins/wordpress-notification-bar/inc/class-plugin.php on line 144

Is the problem the notification bar? That’s a plugin…But I was not able to uninstall it following the discretion from Common_WordPress_Errors .