You need to look for all the files in that directory using Directory.GetFiles(string path, string pattern)
.
Dim files As String() = Directory.GetFiles("\FilePath", "1*")
If files.Length > 0 Then ' file found
Dim file3dopen As New ProcessStartInfo()
With file3dopen
.FileName = files(0)
.UseShellExecute = True
End With
Process.Start(file3dopen)
Else
'file not found
MsgBox("No Such File Exists")
End If