What actually is a registry of a P.C and what is the importance of it? how can one efficiently maint

What are firewalls and is there a possibility of computer hijack if we have an internet connection and don't have a proper firewall protection. Actually i guess it is present in windows i.e., windows firewall is it ok or should we download it from some other sources.

What actually is a registry of a P.C and what is the importance of it? how can one efficiently maintain it?anti virus

The answers that have been posted describe the firewall/registry.

As to changing firewall, yes you need to download a new firewall. Microsoft Windows Firewall is not really a firewall because you only get one way protection from rogue incoming traffice. A true firewall as to be two way protection. Protects you from incoming rogue packets and protects the personal data in your PC from leaving without your permission.

Recommend that you turn off Windows firewall. Go to start, open control panel, open securty and shut down the firewall. You can only have one firewal.

I used Zone Alarm free for over ten years and never has one rogue packet entered by PC. Plus you get auto. updates of all new versions downloaded over the old version. (Recommend when new versions download that you perform a clean install. (This means that you will have to instruct Zone Alarm all over again as to what you will allow and not allow. Zone Alarm recommends the same).