Some do, some don't. It's a BIOS issue. If your BIOS does, it's in some menu and may have words like USB, Keyboard, Mouse and/or Emulation.
But you elected to tell nothing about the host machine so this is all I can offer.
I have microsoft's bluetooth desktop keyboards and mouse set, the shingle which comes with the set is connected to one of the four USB 2.0 ports on the motherboard.
now here's the problem. I have two OS on my system, windows xp professional and windows vista business, when starting the machine, cold boot, we usually come across the initial screen where RAMs are counted and then comes the screen where we have to choose between the two OS systems, now here's the catch, during all that time, no matter how much I tried to use my keyboard to choose an operation system or even go into the boot screen, using the del or esc keys, nothing happens. I end up connecting another microsoft keyboard that has both a USB and serial connection, through the serial connection only, where the system responds, and moves on to open the OS windows for me.
can someone tell me why does this happen, why doesn't the system respond to my bluetooth keyboard?