Before answering this I think we're going to need more details:
Is the keyboard USB or PS/2?
Have you tried it in other ports?
Have you tried starting the PC without the keyboard and then plugging it in once windows has loaded? (assuming it's USB).
Has this keyboard worked on this PC before, or is this a new PC?
Also, you mention in the title (but not the post) that this issue extends to the mouse as well, are they a wireless combo or otherwise bundled together?