To go along with Myles Grey's topic of how to run
ASP on Windows Vista, I will make a topic on how to install ASP.NET on an XAMPP Installation.
First off, if you have not already, download and install XAMPP, which can be downloaded at
www.apachefriends.org You will then need to download the ASP Installer at
SourceForge, so download it, then run it. Choose to of course install it, but you will need to make sure that the install path is set to your Apache directory.
If you have installed XAMPP in C:\xampp\ your path for installing should be C:\xampp\apache\ then hit install, and you are almost done
Now open up C:\xampp\htdocs\apache\conf\extra\httpd-xampp.conf
You will need to add this between the <IfModule alias_module></IfModule> tags
#asp.net
LoadModule aspdotnet_module "modules/mod_aspdotnet.so"
AddHandler asp.net asax ascx ashx asmx aspx axd config cs csproj licx rem resources resx soap vb vbproj vsdisco webinfo
<IfModule mod_aspdotnet.cpp>
AspNetMount /SampleASP "c:/xampp/asp_docs"
Alias /SampleASP "c:/xampp/asp_docs"
<Directory "c:/xampp/asp_docs">
Options FollowSymlinks ExecCGI
Order allow,deny
Allow from all
DirectoryIndex index.htm index.aspx
</Directory>
AliasMatch /aspnet_client/system_web/(\d+)_(\d+)_(\d+)_(\d+)/(.*) "C:/Windows/Microsoft.NET/Framework/v$1.$2.$3/ASP.NETClientFiles/$4"
<Directory "C:/Windows/Microsoft.NET/Framework/v*/ASP.NETClientFiles">
Options FollowSymlinks
Order allow,deny
Allow from all
</Directory>
</IfModule>
#asp.net
Now of course save it, and you will need to restart Apache on your XAMPP Control Panel.
NOTE: Not working? Try this:
http://mschat.net/forum/index.php?topic=574.msg8825#msg8825Then open up C:\xampp\ and create a directory called asp_docs and go into the directory and make index.aspx and put this in it:
<%@ Page Language="VB" %>
<html>
<head>
<link rel="stylesheet"href="intro.css">
</head>
<body>
<center>
<form action="index.aspx" method="post">
<h3> Name: <input id="Name" type=text>
Category: <select id="Category" size=1>
<option>One</option>
<option>Two</option>
<option>Three</option>
</select>
</h3>
<input type=submit value="Lookup">
<p>
<% Dim I As Integer
For I = 0 to 7 %>
<font size="<%=I%>"> Sample ASP.NET TEST</font> <br>
<% Next %>
</form>
</center>
</body>
</html> Save, and open up
http://localhost/SampleASP now if it was successful, you should see something like:
Sample ASP.NET TEST Sample ASP.NET TEST Sample ASP.NET TEST Sample ASP.NET TEST Sample ASP.NET TEST Sample ASP.NET TEST Sample ASP.NET TEST Sample ASP.NET TEST Enjoy!

Source:
http://weblogs.asp.net/israelio/archive/2005/09/11/424852.aspx