Excel VBA File not Found although file exists - excel

Question

I have written below piece of code to access a file and copy content from one file to the other. I am using excel 2007.
Sub copypaste()
Dim strFolder As String
Dim strFileName As String
Dim wb As Workbook
strFolder = "C:\Users\user\Desktop\sample\"
strFileName = Dir(strFolder & "*.xlsx")
Dim eRow
Dim a As Variant
Dim b As Variant
Do While Len(strFileName) > 0
**Set wb = Workbooks.Open(strFileName)**
a = Cells(7, 7)
b = Range("D11:F11")
ActiveWorkbook.Close
Worksheets("sheet1").Cells(7, 7) = a
Worksheets("sheet1").Cells(7, 8) = b
strFileName = Dir
Loop
End Sub
Although the file exists in the folder I get the error while opening the file. While in debug mode the variable strFileName contains the file name but still the file is not opening. I am getting the error at line "Set wb = Workbooks.Open(strFileName)"
Thanks in advance for your help!!

Answer 1

Workbooks.Open requires the full path to the workbook. I suspect you want:
Set wb = Workbooks.Open(strFolder & strFileName)

Answer 2

You need to replace all \ by double \\ in your path
Or add # in front of you string.
It is cause \ is the character for escape strings, like \n \s and so on so letter after a \ is transformed.
Try to print your path, you'll see what append.
EDIT
May also try :
FileToOpen = Application.GetOpenFilename _
(Title:="Please choose a Report to Parse", _
FileFilter:="Report Files *.xls (*.xls),");
Set wb2 = Workbooks.Open(Filename:=FileToOpen)

Answer 3

As (gone) user user496736 stated you need to have a full path
But most of the time your path will be very long and cumbersome to type or you will not know it in advance, so the help of ActiveWorkbook.Path
Exemple with readonly just for information
Dim Alloc_WB As Workbook
Dim FileStr As String
FileStr = ActiveWorkbook.Path & "\" & "my_file.xlsx"
'workbook should be closed at start of code. Otherwise you get an error msg asking to re-open the Workbook
Set Alloc_WB = Workbooks.Open(Filename:=FileStr, ReadOnly:=True)
'...
'Other actions here...
'...
With Alloc_WB
.Close
End With