Glossary → Desktop PC Repair Terms
What Is BIOS?
The firmware that starts your computer before Windows does.
Definition: The BIOS is firmware stored on a chip on the motherboard. It wakes up the hardware, runs the POST check, and finds the drive to start Windows from. Modern PCs use a newer version called UEFI, but most people still call it the BIOS.
BIOS problems we see
“No bootable device” or “Reboot and select proper boot device” errors, a PC that goes straight into the BIOS menu every time, settings that won’t stick, or a PC that stopped starting after a BIOS update was interrupted.
Boot order and drives
A “no boot device” message doesn’t always mean your files are gone. The BIOS may simply be pointing at the wrong drive, or the SSD may not be detected. We check the drive’s health before anything else.
Updating the BIOS safely
Only update the BIOS if you need a specific fix, such as support for a new processor. Never switch off the PC during an update; a power cut mid-update can stop it starting at all.
Related terms
→ CMOS Battery — keeps BIOS settings saved while the PC is off
→ POST — the hardware test the BIOS runs at startup
“No boot device” error?
Free diagnosis, with your drive checked before anything is changed.