For the file you CAN open, try this.
If you do not see "developer" in your tool bar:
Click the Microsoft Office Button Office button image , and then click Excel Options, PowerPoint Options, or Word Options.
Click Popular, and then select the Show Developer tab in the Ribbon check box.
Press Alt+F11 (or click on Visual Basic in the developer tab) to bring up the VBA editor.
Create a new macro by clicking on the arrow next to the button with the ruler on it:

Copy the following code and paste it into your new module:
Sub PasswordBreaker()
'Author unknown
'Breaks worksheet password protection.
Dim i As Integer, j As Integer, k As Integer
Dim l As Integer, m As Integer, n As Integer
Dim i1 As Integer, i2 As Integer, i3 As Integer
Dim i4 As Integer, i5 As Integer, i6 As Integer
On Error Resume Next
For i = 65 To 66: For j = 65 To 66: For k = 65 To 66
For l = 65 To 66: For m = 65 To 66: For i1 = 65 To 66
For i2 = 65 To 66: For i3 = 65 To 66: For i4 = 65 To 66
For i5 = 65 To 66: For i6 = 65 To 66: For n = 32 To 126
ActiveSheet.Unprotect Chr(i) & Chr(j) & Chr(k) & _
Chr(l) & Chr(m) & Chr(i1) & Chr(i2) & Chr(i3) & _
Chr(i4) & Chr(i5) & Chr(i6) & Chr(n)
If ActiveSheet.ProtectContents = False Then
MsgBox "One usable password is " & Chr(i) & Chr(j) & _
Chr(k) & Chr(l) & Chr(m) & Chr(i1) & Chr(i2) & _
Chr(i3) & Chr(i4) & Chr(i5) & Chr(i6) & Chr(n)
Exit Sub
End If
Next: Next: Next: Next: Next: Next
Next: Next: Next: Next: Next: Next
End Sub
Ctrl+S to save, then close the VBA editor.
In your workbook, go to the developer tab and click on Macros. Select PasswordBreaker and click Run.
I've tested this in a couple different worksheets and it seems to do the trick. Your mileage may vary.
You say "One excel file can’t be opened/ edited without entering correct password.", which is it? Can you open the file? Also, do you have any VBA experience? – jrichall – 2017-02-01T18:24:37.223
It looks like you tried to use the tool in the answer to the question you linked to, but did you try the methods in the question it was marked a duplicate of? Try the answer given here and see if that does the trick.
– jrichall – 2017-02-01T20:50:48.647In what version of Excel you created the password protected file i.e. the file that won't open unless you provide the correct password in the first place? – patkim – 2017-02-01T22:11:53.547
As I mentioned, I have two excel files and I believe it was created on 2007 edition. I can't open one excel file and i can open another excel file but Protect Sheet is enabled in this file. I don't know about VBA. I downloaded some softwares but no software worked find. – InTech – 2017-02-04T20:09:28.613
Sorry for the late response, I didn't get a notification. I think I have something that will help with the file you can open. Still looking into the one you cannot. I'll post an answer soon. – jrichall – 2017-02-09T20:11:58.120