环境：WIN2003+SQL2000+IIS+应用软件
软件为B/S结构，最近访问软件时出现错误（服务器重启后又恢复正常，几乎每天都要重启一次，每次出问题的时候在服务器上也无法正常打开外网网页，但网络是通的，重启IIS也不行），高手帮忙解答一下应该怎么解决这个问题
错误提示如下：
Server Error in '/zhongye' Application.
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用户 'sa' 登录失败。
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.
Exception Details: System.Data.SqlClient.SqlException: 用户 'sa' 登录失败。
Source Error:
Line 20: protected void Page_Load(object sender, EventArgs e)
Line 21: { Line 22: titlename = CommonApplication.GetCompanyName();Line 23:
Line 24: if (!IsPostBack)
Source File: d:\富通软件\trade\Admin\Login.aspx.cs Line: 22
Stack Trace:
[SqlException (0x80131904): 用户 'sa' 登录失败。]
jr.Source.Selection.exeSql(String sSql) +61
jr.Source.CommonApplication.GetCompanyName() +19
Admin_Login.Page_Load(Object sender, EventArgs e) in d:\富通软件\trade\Admin\Login.aspx.cs:22
System.Web.Util.CalliHelper.EventArgFunctionCaller(IntPtr fp, Object o, Object t, EventArgs e) +15
System.Web.Util.CalliEventHandlerDelegateProxy.Callback(Object sender, EventArgs e) +34
System.Web.UI.Control.OnLoad(EventArgs e) +99
System.Web.UI.Control.LoadRecursive() +47
System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +1061
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Version Information: Microsoft .NET Framework Version:2.0.50727.42; ASP.NET Version:2.0.50727.42
