A couple of weeks ago I got a ticket from one of my clients regarding a funny little problem that only affected the Administration of the Contacts component on their site. Since then I have noticed the problem popping up on several websites, which on the surface of it didn't seem to have much in common. The solution to the problem however was (in these cases) quite simple, even if it required a little fiddling around to find.
When the site administrator tries to change contacts using the 'Contacts' component (in 'Components > Contacts'), all information is displayed normally, but all the buttons at the top of the component ('Save', 'Save & Close', 'Save & New', 'Save as Copy' and 'Close') are completely inactive.
All of the websites I could find this problem on were using a 'Captcha' solution called 'Osol Captcha' to increase the security of their on-line form solutions.
Joomla has its own 'Captcha' solution built in, so installing a new solution is in most cases unnecessary. Just browse into the Joomla 'Plug-in Manager' ('Extensions > Plug-in Manager'). Use the filter above the plug-in list to search for 'osolCaptcha'. In the list you should now only have one line, containing 'System - osolCaptcha'. Click on the green (Publish) icon to the left of the plug-in title to disable the plug-in.
You can also un-install the plug-in using the Extension Manager Manage functionality. Browse to 'Extensions > Extension Manager' and click 'Manage'. Once there use the filter box to search for 'osolCaptcha'. Tick the little box to the left of 'System - osolCaptcha' and click the 'Uninstall' button at the top of the manager.