Terminal Services svc cause 100% proc ut

Troubleshooting a client’s Dell Inspiron 8200 running XP Pro SP1 for unbearable slowness I found the Terminal Services service to be the culprit. As soon as the service was stopped, processor utilization dropped from 100% to normal (0%-5%) and the notebook has functioned properly. I have disable the service.
After many hours of research I’ve found no information to suggest a cause for this behaviour. What would cause this service to suddenly go rogue?