Have a look at the Hyperlink
object reference:
https://msdn.microsoft.com/en-us/library/office/ff835563.aspx
You should be able to open the file with the .Follow
method, or if that doesn't work you can always grab the .Address
property and pass that to the Workbooks.Open
method.
Also bookmark the Excel Object Model Reference for future use :)
I don't think this works on formula hyperlinks, though, so if that's your situation then instead, do:
Sub h()
Dim cl As Range
Dim h As String
Set cl = Range("E13") 'Modify to the cell containing your =HYPERLINK formula
h = Replace(cl.Formula, "=HYPERLINK(", "")
h = Replace(h, ")", "")
h = Replace(h, Chr(34), "")
h = Split(h, ",")(0)
Dim wb As Workbook
Set wb = Workbooks.Open(h)
End Sub