I just downloaded the Kaspersky Anti virus 2010 version. I cannot install this unless I uninstall the older version. How do I uninstall it? It would be helpful if some one gave me a step by step answer.

Here is the link that you need.
Uninstallation (http://support.kaspersky.com/faq/?qid=208279380)

You can also do this:
Start Bar
Control Panel
Add/Remove Programs
Find the program you want to uninstall
Click 'Uninstall'