It sounds like the Start Menu layout got reset, which usually happens when Windows rebuilds its configuration after a system change or profile glitch.
Since you mentioned adjusting BIOS and battery issues, that likely triggered Windows to reload a default layout, removing your pinned apps and widgets.
The quickest way to fix this is to restart Windows Explorer through Task Manager, then re-pin your apps manually.
If the tiles for built-in apps like Weather or News are missing, you can restore them by opening PowerShell as admin and running a command to re-register all default apps.
Also, check if your Windows version recently updated, because updates can sometimes reset Start Menu settings.
Do you remember if any updates were installed after you fixed the BIOS date?
Or did you notice any error messages when the Start Menu changed?
Regards,
Aron