fileread fileopen and closehandle?

hi i am trying to write something like this
the program will open the text file containing lines like

Code:

H = 1
0 = 16

and then in the dialog's edit box i am going to write H20 (water molecule)
and the program will calculate the mass (2xh + 0) and print it on a static (18g Smile

)

but now i am in the beginning and dealing to open the file including the constant masses

Code:

  data_file file 'data.txt'
  data_file_handle dd ?

section '.code' code readable executable

  start:

        invoke  GetModuleHandle,0
        invoke  DialogBoxParam,eax,37,HWND_DESKTOP,DialogProc,0
        or      eax,eax
        jz      exit
  exit:
        invoke  ExitProcess,0

proc DialogProc,hwnddlg,msg,wparam,lparam
        enter
        push    ebx esi edi
        cmp     [msg],WM_COMMAND
        je      wmcommand
        cmp     [msg],WM_CLOSE
        je      wmclose
        xor     eax,eax
        jmp     finish

  wmcommand:
        cmp     [wparam],ID_Close
        je      wmclose
        jmp     processed
  wmclose:
        invoke  _lclose,[data_file_handle]
        invoke  EndDialog,[hwnddlg],0
  read:
        invoke  OpenFile,data_file,0,OF_READ
        mov     [data_file_handle],eax
  processed:
        mov     eax,1
  finish:
        pop     edi esi ebx
        return

this crashes when exited
i think there are lots of imaginary things i have tried here Smile

some help needed ( at least just show me the way )
for example getting one line of code or one character with readfile and putting it into static control will be great
please dont get rid of this newbie Smile