The BIOS Doesn't Detect the Keyboard or Mouse: What to Do
Why it happens (even though they work fine in Windows), and the specific causes, including gaming mode.
You need to enter the BIOS/UEFI and the keyboard or mouse doesn't respond there, even though they work normally inside Windows. There's a specific technical explanation for this, it isn't a random glitch.
The technical cause
Windows uses full drivers for your peripherals, but the BIOS/UEFI only has very basic built-in support — if that basic support is off or misconfigured, the device works perfectly in Windows but is invisible to the BIOS.
1. Turn on "USB Legacy Support" in the BIOS
This is the most common cause. The catch is that you precisely need the keyboard to navigate the BIOS and turn this option on — this can usually be done from keyboards that already have it enabled by default, or by trying a restart after "Load Optimized Defaults" (factory settings), which usually turns it on automatically.
2. A little-known finding: "gaming mode"
Tip: if you use a "gaming" keyboard or mouse with its own software (Razer, Logitech G, Corsair...), some have a physical "BIOS mode" or "standard mode" switch separate from normal mode — advanced gaming mode sometimes uses a communication protocol the BIOS doesn't understand. Look for that switch on your specific device, or check the manufacturer's website.
3. Try another USB port
Especially relevant on desktops: some USB ports (usually the ones at the back, connected directly to the motherboard) have better BIOS support than the front ones, which sometimes go through an internal hub.
4. If you have a spare PS/2 keyboard
PS/2 ports (the round connector, older than USB) almost always work in the BIOS with no additional adjustment, precisely because they don't depend on the same detection system as USB. If you have one handy, it's a fast way to rule out the problem while you calmly sort out the USB one.
5. Reset the BIOS to factory settings
If none of the above works, resetting the BIOS (usually a "Load Optimized Defaults" option inside the BIOS itself, or removing the motherboard's CMOS battery for a few minutes) usually returns basic USB support to its default working state.
Warning: removing the CMOS battery requires opening the computer's case. If you're not comfortable doing that, it's better to ask someone with experience for help rather than force internal components.
Frequently asked questions
Why does my keyboard work in Windows but not in the BIOS?
Because Windows uses full drivers, while the BIOS only has very basic built-in USB support. If that basic support ('USB Legacy Support') is off, the keyboard works in Windows but is invisible in the BIOS.
Do gaming keyboards and mice cause more problems in the BIOS?
Some do, if they have an active advanced 'gaming mode' with a communication protocol the BIOS doesn't recognise. Many include a specific switch or alternative mode for BIOS — check the device's manual.
Does a PS/2 keyboard always work in the BIOS?
Almost always yes, because it doesn't depend on the same detection system as USB. It's a good way to rule out the problem while you sort out the USB keyboard's settings more calmly.