Plugin Blocking Admin access- Lock me out

I have used your plugin ‘Advanced Access Manager’ and had a problem where I couldn’t access the full dashboard in admin mode so I deleted the plugin and now found, as many in the support forum, that I have can’t revert back to normal again. I can’t access the plugin or the theme area etc.. Could you please help me. Is there a simple fix like deleting the .htacess or something so I can reinstall the software safely?

I have reinstalled the whole files from a restored older backup and still I have no access. Is the issue in the database?

Please help me restore this back to a normal state where I can reinstall your plugin correctly and understand how to avoid the problem in future.

Thank you for your help.

http://wordpress.org/plugins/advanced-access-manager/