I am using an Artisteer template and as captcha not showing (and also affecting the "send" button, I have read some of the threads re other templates.
My html/com-content folder only contains "archive, article, category and featured folders"
this site is still being built on my localhost. I have successfully used other captcha extensions before, but on 1.6, also on artisteer template.
Check the source code of the output and adjust the search string. If you want, then upload the whole source (Right click - Show source) as a text file here and I could try to find the correct search string.