Checking Records in multiple screens using module pool programming

Hi,

    I created student registration form using module pool programming.In first SCREEN i designed like the Below.

          Name:     <INPUT/OUTPUT Field>

         Emailid:    <INPUT/OUTPUT Field>

         Password:<INPUT/OUTPUT Field>

          CREATE<Push Button>    SIGNIN<Push Button>       cancel<Push Button>

in  screen 1000 I created like the above screen and i wrote the code for it.It's successfully inserted records in ZSTUDENT database.

BUT

    when i call the second screen 2000.I design the screen like below.And database table is ZSTU_LOGIN.

      username : <INPUT/OUTPUT Field>

     password  : <INPUT/OUTPUT Field>

         LOGIN<push Button>   EXIT<Push Button>

AND i created Third screen 3000.Like full of detail of student details like First Name,Last Name,DOB,Education Details,Contact Details etc...

BUT I'm facing the pbm is

              whatever the record is stored in table ZSTUDENT-Name & password when i call the screen 2000 that USERNAME & PASSWORD are same

Then go to THIRD screen 3000.BUT i wrote the code for second screen 2000 by using SELECT statement.without my code check it will go to third

screen 3000 By the Statement of Call screen 3000.

PLZ any one help me HOW to CHECK the Exact Record From second Screen 2000 to First Screen 1000.

HOW to Check the code AND can u provide me any code available.

thanks,

Anusha