If you buy a new OEM computer these days, it will most likely come supplied with a USB keyboard and mouse. It wasn’t always this way.
Early IBM clone computers used a 5 pin DIN port for the keyboard and a 9 pin ‘D’ serial port for the mouse. These were replaced by the IBM PS/2 type connectors. PS/2 keyboards and mice generally had grey or black plugs attached to them, and these changed to purple (keyboards) and green (mice) when motherboard manufacturers decided to make it easy for anybody connecting up a system. It was a great idea which overcame the mystery of why the keyboard and mouse were not working. To explain, the keyboard and mouse ports were essentially the same, and it was very easy to cross connect them.
USB enables the input devices to be connected to any USB port on the computer. No problems?
Supposing you have a computer on which you have traditionally used a PS/2 keyboard and mouse. If you connect a USB keyboard and mouse, Windows XP/Vista/Win 7 will eventually acknowledge their presence and will advise you that drivers are being installed. OK, so next time you boot, your keyboard and mouse will be active as soon as Windows starts. So far so good.
So, one day you venture into a Windows newsgroup or forum with a problem you would like answered, and a meanie like me tells you that you will have to go into the system BIOS or setup and make changes to a boot priority list, for instance. If you have an older computer (look on the front panel for a diskette drive), there are a couple of BIOS settings which may not be set as ‘enabled’ by default.
One of them is ‘USB Keyboard’ which allows the computer to recognize the USB keyboard as soon as the computer is powered up. Enabling this one will allow you to access the System BIOS by pressing DEL or F2 or whatever. Now, your computer and Windows will recognize your new USB keyboard. There generally isn’t a ‘Legacy Mouse’ setting because the system BIOS does not allow for a mouse to be used, so there is no point enabling such a feature.
The other BIOS setting which will most likely be disabled by default is ‘Legacy USB’. If you enable this one, you could theoretically use a USB flash drive to boot into the operating system or maybe start an OS recovery process. If you haven’t caught on, I am suggesting that you enable it NOW..
A quickie reminder about hooking up a wireless keyboard and mouse (desktop set). RTFM !!!!
There is a procedure which one has to follow to the letter in order that the setup does not incur tears before bedtime, and that procedure is in the ‘fine’ manual, OK?