The firmware setup screen, still widely called the BIOS even though modern machines use UEFI, is where the laptop configures itself before the operating system loads. Most of it should be left alone. A short list of settings genuinely matters, and a slightly longer list can prevent the machine from booting if you change it without knowing why. This is the map of which is which.
How to reach it, and the golden rule
You enter firmware setup by pressing a key immediately at power on, commonly one of the function keys or delete, though it varies by maker. The golden rule once inside: change one setting at a time, note what you changed, and know how to undo it. Almost every firmware has a load defaults option, which is your safety net if something stops working.
The settings worth knowing
| Setting | What it does | Touch it? |
|---|---|---|
| Boot order | Which device the machine tries to boot from first | Yes, for installing a system from USB |
| Secure boot | Blocks unsigned boot code as a security measure | Rarely, and turn it back on after |
| Virtualisation | Enables hardware support for virtual machines | Yes, if you run virtual machines or containers |
| Fan and thermal profile | Sets how aggressively the fans respond to heat | Sometimes, to trade noise against temperature |
| Memory profile | Runs memory at its rated speed rather than a safe default | Occasionally, if supported and stable |
| Storage mode | How the drive controller presents storage | Only when a new drive is not detected |
Boot order and installing a system
The single most common legitimate reason to enter firmware is to boot from a USB drive to install or repair an operating system. You either change the boot order so USB comes first, or use a one-time boot menu that many machines offer with a separate key. This is the step the guide on reinstalling a laptop system cleanly depends on, and it is entirely safe to change and change back.
Secure boot, and why to leave it on
Secure boot checks that the code loaded at startup is signed and trusted, which blocks a class of low-level malware. It occasionally needs disabling to boot certain alternative operating systems or older installation media, but for everyday use it should stay on. If you turn it off for a specific reason, turn it back on afterward. It is a genuine security feature, not an obstacle to remove for convenience.
Virtualisation, fans, and memory
Virtualisation support is off by default on some machines and needs enabling before virtual machines or containers will run, which is the one firmware change many people genuinely need and never find. If you plan to experiment with the kind of projects described in the guide on what small computers and virtual environments are good for, this is the toggle to check first.
Fan and thermal profiles, where a machine exposes them, let you trade noise against temperature. A quieter profile runs hotter and may throttle sooner; a performance profile runs louder and cooler. Neither is dangerous, since the processor protects itself regardless, and the interaction is the same one covered in the piece on what fan noise indicates. Memory profile settings run your memory at its rated speed rather than a conservative default, which mainly benefits integrated graphics, as the article on how much memory a laptop needs explains. Enable it only if the machine stays stable afterward.
The settings that can stop a boot
Some firmware options will prevent the machine starting if set wrong. Changing the storage mode after a system is installed can make the drive unbootable until you change it back. Disabling secure boot while an operating system expects it, altering how memory is mapped, or toggling low-level options you do not recognise can all leave you at a black screen. This is why the one-change-at-a-time rule matters, and why load defaults exists.
If a firmware change stops the machine booting, do not panic and do not assume the machine is broken. Re-enter firmware, load defaults, and start again. Firmware settings are not permanent damage; they are configuration, and configuration can be reset. Genuine failure to boot from hardware is a different problem, covered in the guide on why a laptop will not turn on, and it behaves differently from a firmware misconfiguration. The physical build of the machine, discussed under what chassis materials tell you, has nothing to do with these settings but is worth understanding alongside them. And if a wireless card swap is what brought you here, some firmware restricts which cards it accepts. Check the machine’s own documentation before buying a replacement card, since the firmware has the final say.
Updating firmware, and when to bother
Firmware itself can be updated, and manufacturers release updates that fix bugs, improve compatibility, and occasionally patch security issues. Unlike changing a setting, a firmware update rewrites the firmware itself, so it carries a small but real risk: an interruption partway through, such as a power loss, can leave the machine unable to start. For that reason, apply firmware updates only from the manufacturer, only when plugged in, and only when there is a reason to, such as a fix for a problem you actually have.
There is no benefit to updating firmware for its own sake. If the machine works, a firmware update is an unnecessary risk. If you have a specific problem the release notes say it fixes, or you are installing new hardware that needs it, then it is worth doing carefully. This is the opposite of the advice for the operating system, where staying current matters, and the difference is that firmware updates are riskier and rarely necessary.
Frequently asked questions
Should I change my BIOS settings?
Only for a specific reason, one setting at a time, knowing how to undo it. The common legitimate changes are boot order for installing a system, enabling virtualisation, and adjusting a fan profile. Leave anything you do not recognise alone, because some settings can prevent the machine booting, and use load defaults if something breaks.
What is secure boot and do I need it?
Secure boot checks that startup code is signed and trusted, blocking a class of low-level malware. For everyday use, yes, keep it on. It occasionally needs disabling to boot certain alternative systems or older media, but turn it back on afterward. It is a real security feature rather than an obstacle.
How do I enter my laptop BIOS?
Press the firmware key immediately at power on, before the operating system loads. It is commonly a function key or delete, but it varies by manufacturer, and the correct key is usually shown briefly on the startup screen or in the machine’s documentation. Many laptops also offer a one-time boot menu on a separate key.
