My computer comes up when I start windows xp home and when it gets to the logon

I start windows xp home and it looks like it is starting but whe it gets to the screen where you click on the user...there are no users listed it's just blank. I put the xp home cd in and ran a repair and it still didn't fix it. Now, it won't even boot from cd. I changed it to boot from cd but it won't give me the screen where I can reinstall windows xp.
I try to start in safe mode and I can't move my arrow keys to choose safe mode then it just tries to restart normally and brings me back to the screen where there is no where to logon...please help!