There are a bunch of apps out there willing to tell you what errors you have in the registry. But consider the following.
Take a brand new install of Windows and run one of these registry checkers and it reports more than a hundred errors.
-> How can that be?
When it comes to an antivirus you are the best person for the job. You decide to install this or that, open some attachment or not and where to go on the internet. There is no better protection than what the user can provide.