1.12 MB ZIP archive labeled L450 with the board code LA-5821. L450 suggests a laptop model, but the brand is not stated, and the contents are not listed. LA-5821 resembles Compal board numbering. Extract the archive to see whether it holds a schematic, boardview or firmware, then use it to trace rails or locate components. Compare the code printed on the PCB first, as suffix letters and revisions can differ. If firmware is inside, back up the original chip before flashing.
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 .zip file
Compressed archive that every operating system opens without extra software.
Built-in OS tools7-Zip