Hello, i have windows XP recently reformat.Initially the USB keyboard was working fine. After few days,keyboard shows few issue such as typing wrong keys or funny char (sticky keys).In midst of troubleshooting that issue,keyboard completely down. Thought it was keyboard issue and changed new one,but problem persist and keyboard spoiled. We changed the keyboard three time.Thought usb issue but other mouse and pendrive works fine. Tried ps2 but issue remain same. weird and comlicated
More aboutboth keyboard working
some times for ps2 keyboard to work you have to cold boot a machine otherwise the keyboard or mouse is not detected correctly, if you can use the mouse see what device managers says about the input devices connected to the pc.
As you did the reinstall recently, the best solution may be to reinstall again. But check Device Manager first.