What's wrong with w32Dasm_2002828_pll621

WIN2000 with sp3 and use w32Dasm_2002828_pll621.exe
I saved unASM file to disk, when I open it again,some codes were changed:

-------------------------------------------------------------------------------
* Referenced by a (U)nconditional or (C)onditional Jump at Address:
|:0079FF1B(C)
|
:0079FF22 8D4C2408 lea ecx, dword ptr [esp+08]
:0079FF26 8BD7 mov edx, edi
:0079FF28 8BC6 mov eax, esi
:0079FF2A E80DF7C6FF call 0040F63C
:0079FF2F FF74240C push [esp+0C]
:0079FF33 FF74240C push [esp+0C]
:0079FF37 8B433C mov eax, dword ptr [ebx+3C]
:0079FF3A 50 push eax
:0079FF3B 8D44241C lea eax, dword ptr [esp+1C]
:0079FF3F 50 push eax
:0079FF40 8B4B38 mov ecx, dword ptr [ebx+38]
:0079FF43 33D2 xor edx, edx
:0079FF45 33C0 xor eax, eax
:0079FF47 E808F7C6FF call 0040F654
:0079FF4C 8D442418 lea eax, dword ptr [esp+18]
:0079FF50 50 push eax

-------------------------------Saved then Opened--------
U)nconditional or (C)onditional Jump at Address:
|:0079FF1B(

|
:0079FF22 8D4C2408 lea ecx
dword ptr [esp+08]
:0079FF26 8BD7
mov edx, edi
:0079FF28 8BC6
mov eax, esi
:0079FF2A E80DF7C6FF
call 0040F63C
:0079FF2F FF74240C
push [esp+0C]
:0079FF33 FF74240C push [es
0C]
:0079FF37 8B433C mov
ax, dword ptr [ebx+3C]
:0079FF3A 50 pus
eax
:0079FF3B 8D44241C lea
ax, dword ptr [esp+1C]
:0079FF3F 50 pus
eax
:0079FF40 8B4B38 mov ecx
dword ptr [ebx+38]
:0079FF43 33D2
xor edx, edx
:0079FF45 33C0
xor eax, eax
:0079FF47 E808F7C6FF call 004
654
:0079FF4C 8D442418 lea

, dword ptr [esp+18]
:0079FF50 50
push eax