java连sql异常

连接数据库代码:
Class.forNam( "com.microsoft.jdbc.sqlserver.SQLServerDriver ").newInstance();
conn = DriverManager.getConnection( "jdbc:microsoft:sqlserver://localhost:1433;DatabaseName=test ", "sa ", " ");
stmt = conn.createStatement();
rs = stmt.executeQuery( "SELECT * FROM Counter ");
我已经把msbase.jar;mssqlserver.jar;msutil.jar三个jar包放到了jdk的lib文件夹里,并在环境变量CLASSPATH中加入了路径:.;D:\Files\Java\jdk1.5.0_08\lib\tools.jar;
D:\Program Files\Java\jdk1.5.0_08\lib;
D:\Program Files\Java\jdk1.5.0_08\lib\dt.jar;
D:\Program Files\Java\jdk1.5.0_08\lib\msutil.jar;
D:\Program Files\Java\jdk1.5.0_08\lib\mssqlserver.jar;
D:\Program Files\Java\jdk1.5.0_08\lib\msbase.jar
java连sql异常,但还是抛java.lang.ClassNotFoundException: com.microsoft.jdbc.sqlserver.SQLServerDriver这个异常,sql2000的sp4补丁我也打了,怎么回事啊.

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jar放在lib下没用，一定要在classpath中指明三个Jar文件
set classpath=.;D:\Files\Java\jdk1.5.0_08\lib\tools.jar;d:\mssqlserver.jar;....
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同意小鬼的回答，包找不到就是没有被加载，lz可以结贴了