So, Code for Password Strength Indicator looks 
like this:
 
<Ajax:PasswordStrength
ID="PasswordStrength1"
runat="server"
DisplayPosition="RightSide"
StrengthIndicatorType="BarIndicator"
TargetControlID="TextBox1"
PrefixText="Stength:"
Enabled="true"
RequiresUpperAndLowerCaseCharacters="true"
MinimumLowerCaseCharacters="1"
MinimumUpperCaseCharacters="1"
MinimumSymbolCharacters="1"
MinimumNumericCharacters="1"
PreferredPasswordLength="10"
TextStrengthDescriptions="VeryPoor; 
Weak; Average; Strong; Excellent" 
StrengthStyles="VeryPoor; 
Weak; Average; Excellent; Strong;" 
CalculationWeightings="25;25;15;35"
BarBorderCssClass="border"
HelpStatusLabelID="Label1">
</Ajax:PasswordStrength>
  
And Complete Source Code looks like this:
 
<%@
Page Language="C#"
AutoEventWireup="true"
CodeBehind="WebForm1.aspx.cs"
Inherits="Password_Strength.WebForm1"
%>
 <%@
Register Assembly="AjaxControlToolkit"
Namespace="AjaxControlToolkit"
TagPrefix="Ajax"
%>
<!DOCTYPE
html PUBLIC
"-//W3C//DTD XHTML 1.0 Transitional//EN" 
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
 
 <html
xmlns="http://www.w3.org/1999/xhtml">
 <head
id="Head1"
runat="server">
      <title></title>
      <style type="text/css">
     
.VeryPoor
       {
         background-color:red;
         }
         
.Weak
        {
         background-color:orange;
         }
         
.Average
         {
          background-color: 
#A52A2A
         }
         
.Excellent
         {
         background-color:yellow;
         }
         
.Strong
         {
         background-color:green;
         }
         
.border
         {
          border: medium
solid #800000;
          width:500px;                
         }
      </style>
 </head>
 <body>
      <form id="form1"
runat="server">
      <div>
         <Ajax:ToolkitScriptManager
ID="ToolkitScriptManager1"
runat="server">
         </Ajax:ToolkitScriptManager>
      <center>
       Please Enter Password:
<asp:TextBox
ID="TextBox1"
runat="server
TextMode="Password"></asp:TextBox>
      </center><br
/>
      
<Ajax:PasswordStrength
ID="PasswordStrength1"
runat="server"
DisplayPosition="RightSide"
StrengthIndicatorType="BarIndicator"
 TargetControlID="TextBox1"
PrefixText="Stength:"
Enabled="true
RequiresUpperAndLowerCaseCharacters="true"
MinimumLowerCaseCharacters="1"
 MinimumUpperCaseCharacters="1"
MinimumSymbolCharacters="1
MinimumNumericCharacters="1"
PreferredPasswordLength="10"
 TextStrengthDescriptions="VeryPoor; 
Weak; Average; Strong; Excellent"
StrengthStyles="VeryPoor; 
Weak; Average; Excellent; Strong;"
 CalculationWeightings="25;25;15;35"
BarBorderCssClass="border
HelpStatusLabelID="Label1">
        
</Ajax:PasswordStrength>
      </div>
      <br 
/>
      <br /><br
/>
      <br 
/>
      <div>
     
<Ajax:PasswordStrength
ID="PasswordStrength2"
runat="server
DisplayPosition="BelowLeft"
StrengthIndicatorType="Text"
 TargetControlID="TextBox1"
PrefixText="Stength:"
Enabled="true
RequiresUpperAndLowerCaseCharacters="true"
MinimumLowerCaseCharacters="1"
 MinimumUpperCaseCharacters="1"
MinimumSymbolCharacters="1
MinimumNumericCharacters="1"
PreferredPasswordLength="10"
 TextStrengthDescriptions="VeryPoor; 
Weak; Average; Strong; Excellent"
BarBorderCssClass="border">
         </Ajax:PasswordStrength>
      </div>
      <div><br
/><br 
/>
      <center>
      <asp:Label
ID="Label1"
runat="server"
Font-Bold="true"
Font-Size="Medium
ForeColor="Brown"></asp:Label>
      </center>
      </div>
      
      </form>
 </body>
 </html>
 
Output of this program:
 
For Weak Password:
![weak password.png]()
 
For Strong Password:
![Strong Pasword.jpg]()