裝上 vs2010Beta后，原有ASP.NET 2.0 的网站无法访问，把asp.net配置选定4.0并重新编译后才能访问，不知道有办法2.0 4.0 共存吗

在测试服务器上有查询网站， asp.net 2.0 ,vs2008开发的，

今天装上了vs2010beta1，网站无法访问，报错，不知道asp.net2.0和4.0有办法共存吗？

Server Application Unavailable The web application you are attempting to access on this web server is currently unavailable.  Please hit the "Refresh" button in your web browser to retry your request. Administrator Note:

An error message detailing the cause of this specific request failure can be found in the application event log of the web server. Please review this log entry to discover what caused this error to occur.