Sql Server 2008 agent not starting.Not able to connect to db

I am seeing that the SQL server (2008 ) server agent is down .Does not try to start no matter I do.I am thinking because of that I am not able to connect to the database using my JDBC connection string
Here is the error I am getting
I am not able to connect to sqlserver 2008 (on windoes xp).
I get the followign error
java.sql.SQLException: [Microsoft][SQLServer 2000 Driver for JDBC][SQLServer]Login failed for user 'sa'.
      at com.microsoft.jdbc.base.BaseExceptions.createException(Unknown Source)
      at com.microsoft.jdbc.base.BaseExceptions.getException(Unknown Source)
      at com.microsoft.jdbc.sqlserver.tds.TDSRequest.processErrorToken(Unknown Source)
      at com.microsoft.jdbc.sqlserver.tds.TDSRequest.processReplyToken(Unknown Source)
      at com.microsoft.jdbc.sqlserver.tds.TDSLoginRequest.processReplyToken(Unknown Source)
      at com.microsoft.jdbc.sqlserver.tds.TDSRequest.processReply(Unknown Source)
      at com.microsoft.jdbc.sqlserver.SQLServerImplConnection.open(Unknown Source)
      at com.microsoft.jdbc.base.BaseConnection.getNewImplConnection(Unknown Source)
      at com.microsoft.jdbc.base.BaseConnection.open(Unknown Source)
      at com.microsoft.jdbc.base.BaseDriver.connect(Unknown Source)
      at java.sql.DriverManager.getConnection(DriverManager.java:525)
      at java.sql.DriverManager.getConnection(DriverManager.java:171)
      at Connect.getConnection(Connect.java:41)
      at Connect.displayDbProperties(Connect.java:60)
      at Connect.main(Connect.java:96)