It seems your Windows is corrupt. Try doing a repair install. But before doing anything check the bios if first boot is set to cd drive. Press 'del' or 'f2' key to enter setup and make the first boot device as cd drive. You should now be able to boot through your xp cd.
I have this problem with my computer.
One morning I tried to log on to my account and when everything was all booted up, My pc just froze and restarted. I tried many times again. So then I tried going into safe mode and then nothing. Then I went to the alternate safe mode and i got in fine. I then found out it was the fact that if i ran my Webroot Spysweeper, My computer would freeze or reset. So then i downloaded Malwarebytes and it found several threats. Even after this, My computer still won't let me run smoothly though. So now I am currently running my account with Webroot Spysweeper disactivated to run on startup. I've tried many things. chkdsk.exe won't run. When i do it from the command prompt, It said the system is unable to complete the disk check. Then i tried to run it from the RUN and it only showed the command prompt and went away quickly. I'm Running Windows Xp Media center Edition Service pack 2. Let me know if you need to know more.