Is it a keyboard from an older computer?EDITED
The keyboards of older IBM computers back in the 1980's used a different "scancode" (the character set) in the circuitry of the keyboard (up until the 1990's).
After that, the scancode used in new computers and keyboards was changed, but there still were many older computers still in use.
Up until about Y2k (year 2000), many new (store bought replacement) keyboards had a small switch on the back so that you could switch to the older scancode if you still had an older computer.
Usually, the switch was recessed (it was not visible on the surface of the back of the keyboard) and was accessable by sticking a pen/pencil/paper clip through the square hole in the back of the keyboard. Unfortunately, these "switchable keyboards" (the official name) were eventually phased out of production.
So, check on the back of the keyboard, if you see a hole (most likely a square hole) and your computer is older (1990's), you will be able to fix the keyboard problem simply by moving the switch to the other position (the switch only has 2 positions).
If your computer is newer (only 10 years old), but the keyboard has the switch on it, maybe the switch accidently got moved to the wrong position.
Even though alot of keyboards have their own software, I never had to load ANY software that came with a keyboard (I ALWAYS use keyboards just as I buy them,...I just plug it into the back of the computer.
Could it be that there's a password you forgot about?
What screen do you see?....Does it boot at all? Are you sure you're connecting to the keyboard connection and not the mouse connection at the back of the computer?
Some computers will boot up to the Windows screen even when you hook up the keyboard to the mouse connection, some will do nothing except beep and maybe show you a keyboard message.