Give this a shot... This is a copy of an article straight from MSDN. Its
about the tool that I had to run on my box to get VS.NET\ASP.NET\IIS to play
nice. I hope you can read this because is did select, copy and paste. If
you are unable to read it do a search for "aspnet_regiis":
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By default, when the .NET Framework is installed on a computer with an
existing installation, all ASP.NET applications are automatically updated to
use this version of the .NET Framework. The only exceptions are applications
that are bound to an incompatible version of the runtime or to a later
version of the runtime. Although later versions of the .NET Framework are
designed to be backward compatible, you might want to configure an ASP.NET
application to use an earlier version. The following sections describe the
process to configure an ASP.NET application to target a specific version of
the .NET Framework.
Viewing the Script Map for an ASP.NET Application
When managing a computer with multiple versions of the .NET Framework
installed, it is often useful to view the script map for an ASP.NET
application to determine which version is used by the application. You can
view the script map for an ASP.NET application using the Internet
Information Services management console.
To view the script map for an ASP.NET Application
1.. Open the IIS management console, expand the local computer by clicking
the plus sign, and navigate to the folder that contains the ASP.NET
application.
2.. Right-click the folder and click Properties. The application's
Properties dialog box appears.
3.. On the Directory tab, click the Configuration button. The Application
Configuration dialog box appears.
4.. On the Mappings tab, select an ASP.NET application extension, such as
..asmx or .aspx.
The Executable Path column of the dialog box lists the path to the ASP.NET
ISAPI version used by the application. By default, the ASP.NET ISAPI is
installed in the following location:
systemroot\Microsoft.NET\Framework\versionNumber
The version number shown in the path indicates the version number of the
ASP.NET ISAPI used by the application. The ASP.NET ISAPI version determines
which version of the runtime is used by the application.
Updating Script Maps Using Aspnet_regiis.exe
To make it easier to reconfigure the script map for an ASP.NET application,
each installation of the .NET Framework comes with an associated version of
the ASP.NET IIS Registration tool (Aspnet_regiis.exe). Administrators can
use this tool to remap an ASP.NET application to the ASP.NET ISAPI version
associated with the tool.
Note Because Aspnet_regiis.exe is linked to a specific version of the
..NET Framework, administrators must use the appropriate version of
Aspnet_regiis.exe to reconfigure the script map for an ASP.NET application.
Aspnet_regiis.exe only reconfigures the script map of an ASP.NET application
to the ASP.NET ISAPI version associated with the tool.
The tool can also be used to display the status of all installed versions of
ASP.NET, register the associated version of ASP.NET, create client-script
directories, and perform other configuration operations.
To use Aspnet_regiis.exe to update a script map for an ASP.NET application
1.. Open a command window. (Click Start, click Run, type cmd, and then
click OK.)
2.. Navigate to the directory of the Aspnet_regiis.exe version you want to
use. Remember that each version of the .NET Framework comes with its own
version. The file is usually located in the following directory:
systemroot\Microsoft.NET\Framework\versionNumber
3.. Use the -s or -sn option of Aspnet_regiis.exe along with the path to
the application to set up the script maps. The following shows a sample
command line that updates the script maps for an application called
SampleApp1.
Aspnet_regiis.exe -s W3SVC/1/ROOT/SampleApp1Application Pooling in IIS 6.0
IIS versions earlier than 6.0 use the ASP.NET process model (Aspnet_wp.exe).
Under the ASP.NET process model, each unique application version
automatically runs in a separate process at run time. All applications that
target the same version of the runtime share the same process (or processes
in Web garden mode). However, IIS 6.0 uses the IIS 6.0 process model
(w3wp.exe) and introduces a new isolation feature called application
pooling. Application pooling allows applications to run together in one or
more processes, as long as they share the same pool designation.
Applications that are assigned different application pools never run in the
same process.
When multiple versions of the .NET Framework are installed on a computer
that uses IIS 6.0, you might encounter the following error message in the
Application Event log.
It is not possible to run different versions of ASP.NET in the same IIS
process. Please use the IIS Administration Tool to reconfigure your server
to run the application in a separate process.
This error occurs when more than one version of ASP.NET is configured to run
in the same process. Different versions of the .NET Framework and runtime
cannot coexist side-by-side in the same process. Therefore, an ASP.NET
application that uses a particular version of the runtime must not share a
process with an application that uses a different version. This error
commonly occurs when two or more applications are mapped to different
versions of ASP.NET, but share the same application pool.
To use application pooling, first make sure IIS 5.0 isolation mode is
disabled. Next, navigate to the desired application in the Internet
Information Services management console and assign it an application pool.
If you want to isolate your application from the existing application pools,
create a new pool designation.
Note The process isolation for each application is configured manually.
To disable IIS 5.0 isolation mode in IIS 6.0
1.. Open the IIS management console and expand the local computer by
clicking the plus sign.
2.. Right-click the Web Sites folder and click Properties.
3.. On the Service tab, clear the Run Web service in IIS 5.0 isolation
mode check box.
To assign a pool designation to an ASP.NET application in IIS 6.0
1.. Open the IIS management console, expand the local computer by clicking
the plus sign, and navigate to the folder that contains the ASP.NET
application.
2.. Right-click the application and then click Properties. The
application's properties dialog box appears.
3.. On the Directory tab, select the desired pool designation from the
Application Pool list.
To create a pool designation in IIS 6.0
1.. Open the IIS management console and expand the local computer by
clicking the plus sign.
2.. Right-click the Application Pools folder, point to New, and then click
Application Pool. The Add New Application Pool dialog box appears.
3.. Enter the new pool designation in the Application pool text box, and
then click OK.
