Remote desktop only works if someone is already logged in

I'm sure this is incredibly simple but I don't know the answer.

We have an XP SP2 machine that has remote desktop enabled from the MY PC
properties. We can remote into the box after someone logs in locally but
if we reboot the box and no one is logged in, no one can remote desktop into
the box.

Is there a way to enable remote desktop so that people can remote into the
PC even if the PC has just booted and no one has logged in yet?

Thanks