Profile starting pproblem

When starting my PC I get a message with a timer of 30 seconds that says
***User Environment. Windows cannot load User's Profile but has logged on
with the default profile of the system. Detail, The process cannot access the
file because is being used by an other process***. Can someone PLEASE tel me
what other process is using my user's profile so windows is logging with the
default. How can I fix it. Windows XP Pro sp2 and I am the only user of this
computer. Thank you All