Cannot finish boot up

I have a Cisnet Computer with a 60 gig hd and, I think 512K memory. As I was using it today, the mouse arrow started jumping across the monitor. I rebooted the computer and the booting stopped where I type in my password. Now the mouse and keyboard won't work. I cannot type my password in order to finish booting the computer. The fan is working. The switch lite and led light are working. There are no beeping sounds. Everything is plugged in. Multiple reboots from the switch and plug make no difference. I'm using Windows XP home edition. Any idea's? Thanks for advice.