MSI MS-7638 motherboard, revision 1.0, packed in a 2.11 MB RAR archive, larger than most in this group. That size suggests more than one document inside, though the name does not list them. MSI uses the MS-7xxx code for its own desktop board designs. Confirm the board number and Rev 1.0 on the PCB, then use the schematic or layout to check regulator outputs, locate fuses and filter coils, and follow the power-good chain when the board will not start.
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 @IT_SERVICE_WORLD. 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.
7-ZipWinRARThe Unarchiver (macOS)