Why ASP.NET Session is automatically lost?

I hosted ASP.NET Web App. to IIS6. When I run Web App., The w3wp.exe process will terminate and the sessions will be lost. I use traditional In-Process Session State. This Page have many Process to calculate.

But in some machine that also running this Web in IIS6, It can run and have no problem. So this problem occurs in some machine.

My machine is Core2Duo CPU r开发者_如何学运维unning on Windows Server 2003 4GB of RAM

I try to configure IIS6 to disable all events of Worker Process Recycle, but I still cannot work.

What I should do?

Thanks