i want a live site to be on local host and without effecting any functionality of live magento site. i have tried many way of doing that but have not get any result from it.
First of all you will have to change the secure and unsecure base_url in your database.
These can be found in the 'core_config_data' table.
Paths:
web/unsecure/base_url
web/secure/base_url
If you want to access your local version of Magento via localhost, you'll have to set localhost as your base_url.
After that you need to clear your cache folder.
EDIT:
To install and run Magento on your local PC using XAMPP, please follow these steps:
http://www.magentocommerce.com/wiki/1_-_installation_and_configuration/installing_on_windows_with_xampp_and_wamp