Excel VBA SQL Data

First of all you need to add a reference to the ActiveX Data Objects library, which contains the set of objects that allow you to do database access - in the Excel Visual Basic editor, go to Tools|References... In the dialog box, scroll down until you find Microsoft ActiveX Data Objects 2.8 Library. Check the box next to the library name.
VBA References dialog with ADO library checked http://philippursglove.com/stackoverflow/adoreference.png

Your code to update the database should then look something like this (using the SQL from JohnK813's answer):

'Declare some variables
Dim cnn As ADODB.Connection
Dim cmd As ADODB.Command
Dim strSQL As String

'Create a new Connection object
Set cnn = New ADODB.Connection

'Set the connection string
cnn.ConnectionString = myDatabaseConnectionString 'See http://connectionstrings.com if you need help on building this string for your database!

'Create a new Command object
Set cmd = New ADODB.Command

'Associate the command with the connection
cmd.ActiveConnection = cnn

'Tell the Command we are giving it a bit of SQL to run, not a stored procedure
cmd.CommandType = adCmdText

'Create the SQL
strSQL = "UPDATE Test SET YourField = NeValue WHERE IDField = 2"

'Pass the SQL to the Command object
cmd.CommandText = strSQL

'Open the Connection to the database
cnn.Open

'Execute the bit of SQL to update the database
cmd.Execute

'Close the connection again
cnn.Close

'Remove the objects
Set cmd = Nothing
Set cnn = Nothing

I see you have other questions open that deal with actually connection to the SQL Server, so I won't add any more to that discussion.

Relational database tables don't think of things as being in a certain order, so you can't really say that a certain record is "record 2" or "line 2" just because you added it to the table second. Unless of course you use a field to create an ID number that increments with each new record added.

Then you can access that record by saying

UPDATE Test SET YourField=NewValue WHERE IDfield=2

Here's more information on the UPDATE command, if you need it.