I had an email account on an Exchange server for a contract I was working on. The contract ended and my password was deleted from the Exchange server so I could no longer get into the company's email. Now, when I open my IPad it asks for the Exchange password and when I can't supply it I continue to get the message asking for the password. I can't cancel out of this error message, it just keeps coming up whether I hit cancel or supply a no longer valid password. I cannot get into the IPad desktop because I can't get by this message. I would like to delete the Exchange account from my IPad (I was able to do this on my IPhone) but I can't get to the Settings. How can I get by this message? Thanks.
Is it a wifi only iPad? If so, you can try to temporarily shutdown your wifi. If the iPad is not connected to Internet, maybe it won't try to fetch mails.
When you are prompted, have you tried to double click the home button and kill the Mail app? Or maybe try to access Settings from there.
You can also try to connect your iPad to your computer, if it's sync to iTunes. From there, in the Info view of the iPad on iTunes, select that you don't want any email account (I believe there is a overwrite current settings checkbox) and erase your accounts from there. You'll probably have to re-add your others account manually.