Cygnus X-1 on "[Plugin: HumanCaptcha by Outerbridge] Locked out of site, can't get to login screen"

Hi, yes I was using a caching plugin. Can't remember exactly which one, but in cpanel, can see a wp-cachecom folder. I renamed this folder to disable the plugin, but didn't do anything. From cpanel, I tried restoring my site. This did allow me to get back to the login screen and brings up the captcha question again. In this case, the question is "What is the usual colour of the sky on a sunny day?". However, if I type in "blue" it says your captcha answer is incorrect, and I don't think this is a trick question! Refreshing browser doesn't bring up new question.

Any more ideas on how to resolve? I'll re-install wordpress if I have to, but must be an easy fix for this. I would have thought disabling the captcha plugin by renaming it would have allowed me to login again.

Thanks.