If you have C5, then there is an option in the particle modeling room for setting the particles to start BEFORE your timeline. So, if you want to fill the fountain, set it to start earlier, then you can leave your timeline set at Frame '0' and not worry about accidentily animating an object by adjusting while at the wrong frame. (A problem I have struggled with more then once. :(  I was SO glad when they added a Frame '0' to be able to correct for such Operator Errors!)