Would this be correct then?
Code:
 

DIM $NAME, $SERVER, $DB, $user
$NAME='Tempdb ODBC Connection to SVRDB4'
$SERVER='SVRDB4'
$DB='tempdb'
$user=''    

FUNCTION ODBCSQL($NAME,$SERVER,$DB,optional $user)
 DIM $reg,$Title,$Driver,$RegEd,$RegEdPath,$RC
 IF NOT $user
    $reg='HKLM' ; System DSN
 ELSE
    $reg='HKCU' ; User DSN
 ENDIF
 $Title='SQL Server'
 $Driver=READVALUE('HKLM\SOFTWARE\ODBC\ODBCINST.INI\'+$Title,'Driver')

 $RegEd=$reg+'\SOFTWARE\ODBC\ODBC.INI'
 $RegEdPath=$RegEd+'\'+$Name

 IF NOT KEYEXIST($RegEdPath)
  $RC=ADDKEY($RegEdPath)
  $RC=WRITEVALUE($RegEdPath,'Database',$DB,'REG_SZ')
  $RC=WRITEVALUE($RegEdPath,'Driver',$Driver,'REG_SZ')
  $RC=WRITEVALUE($RegEdPath,'LastUser',@USERID,'REG_SZ')
  $RC=WRITEVALUE($RegEdPath,'Server',$Server,'REG_SZ')
  $RC=WRITEVALUE($RegEdPath,'Trusted_Connection','Yes','REG_SZ')
  $RC=WRITEVALUE($RegEd+'\ODBC Data Sources',$Name,$Title,'REG_SZ')
 ENDIF
ENDFUNCTION