As far as you give the directory in which to "search" it is not a real search. Pretty much, everything needed could be just in one line:
ThisWorkbook.FollowHyperlink S:\PROFILE ORDERS\somePdf.pdf
the rest depends on how do you want to aproach it. The code below would throw an error, if there is no such file in the specified directory.
Sub OpenPdf()
On Error GoTo OpenPdf_Error
Dim pdfname As String
Const sPath = "C:\Users\gropc\Desktop\"
pdfname = Application.InputBox("Enter the pdf you are looking for")
pdfname = pdfname & ".pdf"
ThisWorkbook.FollowHyperlink sPath & pdfname
On Error GoTo 0
Exit Sub
OpenPdf_Error:
MsgBox "Error " & Err.Number & " (" & Err.Description & ") in procedure OpenPdf"
End Sub