Repeated error messages

[oldman]

I am getting repeated error messages that are making my Nexus 7 unusable.  Every time  I use it a "Couldn't sign in" (GMail) message appears.  I have changed my password and can sign in on my PC where I have no problems.
I have tried deleting GMail and every other google based app I can find but the error message is repeated ad nausium.
Last night I received an update to 4.4.4 and it is still happening!!
BTW the message pops up in every app its just stopped me using Facebook

[matt]

In settings/accounts delete

sent by mirrorflash Morse code

[matt]

Google by pressing twice and then menu upper right. Re add the account.

sent by mirrorflash Morse code

[oldman]

Thanks Matt that is working, I was getting to the point of despair, especially as I found that Google does not seem to provide any sort of service to its clients 
Next time I'm in Texas I'll buy you a beer 

Tony