ASP.NET: Error "Login failed for user 'sa'."

[Tony]

Dear all,

When running the .ASPX program, I recieved the following error

"Exception Details: System.Data.SqlClient.SqlException: Login failed for
user 'sa'."

I reinstalled Sql Server and issue is fixed. However, the issue occur again
after a while.

In web.config file, the connection setting is below:
"
<appSettings>
<add key="PubsString" value="workstation
id='sha-tongl-xp1';uid=sa;pwd='';server=localhost;initial
catalog='Pubs'"></add>
</appSettings>
"
Any help will be highly appreciated.

-Tony