closing excel in VB

I have a problem with closing excel. I can open excel but I can't close it.
I've tried to this

dim Excelwkbk as object
set ExcelWkbk = Workbooks.Close
ExcelApp = ExcelWkbk.Application
ExcelApp.Close (True)

but it doesn't work

can someone tell me how to solve tis problem

Greetzzzzzzzz

I'll go over opening and closing excel with you from the beginning.

Dim xlApp As Excel.Application
Dim xlWB As Excel.Workbook
'open excel application
Set xlApp = New Excel.Application
'Open excel workbook
Set xlWB = xlApp.Workbooks.Open(Filename:="C:\YourFile.xls")
'do your code here
'Close workbook (optional)
xlWB.Close
'Quit excel (automatically closes all workbooks)
xlApp.Quit
'Clean up memory (you must do this)
Set xlWB = Nothing
Set xlApp = Nothing

thanks for your solution. It works, but it is a solution for using 1 button.

It has to open with a form load and close if I press the button 'End'.

I've tried to use your solution in 2 buttons but I can't make it work.

Same code just move some parts of it to different locations

'Need to declare outside of any Sub
Dim xlApp As Excel.Application
Dim xlWB As Excel.Workbook

Private Sub Form_Load()
'open excel application
Set xlApp = New Excel.Application
'Open excel workbook
Set xlWB = xlApp.Workbooks.Open(Filename:="C:\YourFile.xls" )
'do your code here
End Sub

Private Sub cmdClose_Click()
'Close workbook (optional)
xlWB.Close
'Quit excel (automatically closes all workbooks)
xlApp.Quit
'Clean up memory (you must do this)
Set xlWB = Nothing
Set xlApp = Nothing
End Sub

However, instead of Quitting Excel and setting xlWB and xlApp to nothing with a button I'd suggest doing all of that in the Form_Unload Sub.