HP ProBook 4540s archive in RAR format, 416 KB, marked as the first of two similarly named copies. The name gives no detail about the contents or the motherboard number, so extract it with 7-Zip or WinRAR and check what it holds. It could be a BIOS image or a service document. ProBook 4540s boards came in more than one variant, so confirm that the board number on your PCB matches the files. Always read and save the existing flash contents with a programmer before writing a new image.
The button opens the matching file on RM Schematics, or a source page if it is not catalogued there yet. The original attachment is from @hrtechno. Enginerys does not host this file.
How to open a .rar file
Compressed archive — the usual wrapper for a schematic + boardview pair or a BIOS + EC set.