Kaspersky AntiVirus(KAV) and Kaspersky Internet Security (KIS) has different in it. Take a look.

KASPERSKY INTERNET SECURITY (KIS)    2010 KASPERSKY ANTIVIRUS   (KAV)               2010
Quick Comparison
Protection from:
Viruses and spyware YES YES
Infected Websites YES YES
Hacker attacks YES
Spam and phishing YES
Identity theft YES
Features Comparison
Core Protection
Virus and vulnerability scanner YES YES
Updates to protect new viruses YES YES
Proactive protection against programs based on their behaviour Improved! YES YES
Restriction of access to private data by suspicious programs Improved! YES
Application control Improved! YES
Urgent detection system Improved! YES
Safe run mode (sandbox) to test questionable programs New! YES
Network Protection
Two-way personal firewall YES
Secure wireless connections in public areas YES
Email protection
Real-time scanning of email YES YES
Anti-spam Improved! YES
Anti-phishing Improved! YES
Web protection
Virtual keyboard to safely enter sensitive data Improved! YES YES
Removal of Internet activity (history, cookies, etc) New! YES YES
Color-coding of links to unsafe websites New! YES YES
Safe run mode (sandbox) to test questionable websites New! YES
Parental Control YES
Extended features:
Special game mode New! YES YES
Rescue Disk tool Improved! YES YES
Safe folder for storing valuable or sensitive files Improved! YES

this note is taken from kaspersky official website : http://www.kaspersky.com/renew_popup