vb+sql server数据库连接问题，我是新手，请高手赐教！急。。。

[zhuiyunyiye]

我的连接 ，是无源连接。测试连接成功，可写代码时却说找不到
请高手帮忙解决，不胜感激。。。。
以下是代码：
Option Explicit

Public LoginSucceeded As Boolean

'引用Microsoft ActiveX Data Objects 2.8 Library

'定义连接对象和记录集

Dim conn As ADODB.Connection

Dim rs As ADODB.Recordset


Private Sub Command1_Click()
Set conn = New ADODB.Connection

Set rs = New ADODB.Recordset

'建立无源数据库连接

conn.ConnectionString = "driver={sql server};server=ZHOU-OA65670375;uid=sa;pwd=504121;Database=zhou"

conn.ConnectionTimeout = 50

conn.Open

Dim str As String

'连接连接对象

Set rs.ActiveConnection = conn

'设置游标类型

rs.CursorType = adOpenDynamic

If Trim(Text1.Text = "") Then

MsgBox "用户名不能为空，请重新输入用户名！", vbOKOnly + vbExclamation, "警告"

Text1.SetFocus

Else

'设置查询字符串

str = "select * from User where userid ='" & Trim(Text1.Text) & "'"

rs.Open str

If rs.EOF = True Then

MsgBox "没有这个用户，请重新输入用户名!", vbOKOnly + vbExclamation, "警告"

Text1.SetFocus

Else

'登录成功，连接主窗口

If (Trim(Text2.Text) = Trim(rs.Fields("password"))) Then

LoginSucceeded = True

Me.Hide

Form3.Show

Else

MsgBox "密码不正确，请重输入密码!", , "警告"

Text2.SetFocus

SendKeys "{Home}+{End}"

End If

End If

End If

End Sub

Private Sub Command2_Click()

'设置全局变量为 false

'不提示失败的登录

LoginSucceeded = False

Me.Hide

End Sub

[饮水需思源]

str = "select * from [User] where userid ='" & Trim(Text1.Text) & "'"

[zhuiyunyiye]

运行的时候输入用户名 密码 点确定后出现 ：实时错误【Microsoft】【ODBC SQL Server Driver】【DBNETLIB】SQL Server 不存在或访问被拒绝
点调试就指向程序中的红字 conn.Open

[oybh]

用这个连接字符串
conn.ConnectionString ="Persist Security Info=True;Provider=SQLOLEDB.1;User ID=sa;Password=;Data Source=ZHOU-OA65670375;Initial Catalog=zhou"

[xjy2004]

driver={sql server};server=ZHOU-OA65670375;uid=sa;pwd=504121;Database=zhou
这个串里的属性都正确吗?
SQL Server服务器名称是ZHOU-OA65670375吗?
用户名是sa且有权限吗?
密码是504121吗?
存在默认数据库zhou吗?

[lcsfxs]

'连接字符串
Adodc1.ConnectionString = "driver={sql server};server=" + Trim(server) + ";uid=" + Trim(user) + ";pwd=" + Trim(password) + ";database=erp1"
'查询businessman表中全部信息
Adodc1.RecordSource = "select * from businessman"
'用datagrid显示查询信息
Set DataGrid1.DataSource = Adodc1