Bugs

I have a lot of issues .already informed . My home page is showing some errors automaticaly, like sometimes ajax login works and sometimes not . Layout design sometimes changes. And please please give me a captcha plugin for registering , because too many russian spams and hackers are registering . you have suggested some plugins but none of them worked in the front end .

And also about the updation , how can I update the theme ? should I delete the current version ?

login details already given