How can I use the below code to call an account as
http://www.domain.ext/madcoder
instead of
http://www.domain.ext/index.aspx?key=madcoder
As my madcoder is my primary search key to fetch databse 
I found the following code but couldn't understand how to use it. Anybody please help me.
<rule name="RewriteUserFriendlyURL1" stopProcessing="true">
  <match url="^([^/]+)/?$" />
  <conditions>
    <add input="{REQUEST_FILENAME}" matchType="IsFile" negate="true" />
    <add input="{REQUEST_FILENAME}" matchType="IsDirectory" negate="true" />
  </conditions>
  <action type="Rewrite" url="?p={R:1}" />
</rule>
EDIT 1
I tried modifying my web.config file in the below way which is giving me error
<configuration>
    <system.web>
        <compilation debug="true" targetFramework="4.0"/>
    </system.web>
    <rule name="RewriteUserFriendlyURL1" stopProcessing="true">
        <match url="^([^/]+)/?$" />
        <conditions>
            <add input="{REQUEST_FILENAME}" matchType="IsFile" negate="true" />
            <add input="{REQUEST_FILENAME}" matchType="IsDirectory" negate="true" />
        </conditions>
        <action type="Rewrite" url="index.aspx?key={R:1}" />
    </rule>
</configuration>
 
     
     
    