Avast antivirus is one of my favorite antivirus. It's working very much good for any kind of PC if it is Pentium 3 or 4. Some antivirus work good but they make the computer so much slow due to there high size files, but this antivirus guarantily doesn't slow your computer and will protect your computer from any virus. And the most beautiful point of this antivirus is that it's full registered antivirus for 1 year. You can get all benefits from this antivirus which can be gotten from any other registered antivirus.
Note: This antivirus need password to unzip it. Here is the password.
The key in this file is now expired, when you will download the software, kindly register it with this key. Then it will work till 2038.