My computer doesn't detect my Samsung Galaxy A5 at all on bootloader mode I'm trying to unlock my bootloader on my Samsung Galaxy A5. I've done a lot of research and can't find a solution.

My problem is that whenever I turn on bootloader mode, my computer doesn't even see it, but when I'm on normal mode, the phone is just working normally and my computer detects it.

How can I fix it and unlock my bootloader?
I assume you're trying to "unlock bootloader" in the way you would do to a Nexus, i.e. fastboot oem unlock. Unfortunately Samsung almost never made their bootloaders work like that - the only thing even close is Download Mode + Odin where you use Odin (their proprietary tool) on PC to load stuff like recovery images onto the device.

Since it's not clear what you're intending to do by unlocking bootloader (likely rooting), consider taking a look at XDA for discussions and development specific to your device. You might even find yourself a custom ROM in the end, but no guarantees.