State Server stopped working after installing .Net Framework 1.1 S

[Guest]

I am running an asp.net project on my localhost and using state server as
state management, it has the following code in web.config
<sessionState mode="StateServer"
stateConnectionString="tcpip=MyMachineName:42424" timeout="20"
cookieless="false" />

It had been working fine until I installed
Microsoft .Net Framework 1.1 SP1 (and Windows Update)

I got error"Unable to make the session state request to the session state
server"

I ensure that the ASP .NET State Service is running as .\ASPNET account.

Please advise.