PDF of 189 KB named 2SD2440 and catalogued as a schematic. Under JIS semiconductor numbering the 2SD prefix indicates an NPN bipolar transistor, so this is probably a full component sheet for that part rather than a device circuit. The name states no laptop, board or brand. Its larger size suggests extra curves or packaging information. Use it to look up pin assignment, voltage and current limits and gain groups, then pick a replacement accordingly. Verify the marking on the physical transistor first.
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 @cyberlanelectonik. Enginerys does not host this file.
How to open a .pdf file
The standard format for schematics, block diagrams, power-sequence charts and service manuals.