in order to resolve this problem one of the possible way is

executing a select statement before doing the insertion in the database

create connection to the database…

so ur getting the first and last name in the text box

Execute the following query: (use datareader to execute the query)

“select * from Employee where Fname = ‘” & txtFName.text & “‘ and LName = ‘” & txtLName & “‘”

after executed the query using VS2005 in the execute reader

check

if dr.hasrows() = true
Msgbox(“Name already exist”)
else

endif

so u can prevent the duplication of the first and last name
if u want check only the first or last name provide that one in the select query which u want to check

sample Example: for checking username and password

dim theOleDbCommand = new OleDbCommand(“SELECT [ID] FROM tableName WHERE username = ‘” + this.txtUserName.Text + “‘ AND [Password] = ‘” + this.txtPassword.Text + “‘”);

theOleDbCommand.Connection = new OleDbConnection(connectionStringHere);

theOleDbCommand.Connection.Open();

dim theReader = theOleDbCommand.ExecuteReader(CommandBehavior.CloseConnection);

//you may need to comment out the line below, experiment:

//theReader.Read();

if (theReader.HasRows) then
{

//they logged in, data exists

}

else

{

//error, they don’t exist or the username/password is invalid

}

theOleDbCommand.Connection.Close();