You're going to need to post some code for more specific answers since your descriptions are too vague. For instance, this "Write" and "Start" subVIs are what?
In general, a while loop always runs at least once. The terminal in the bottom right indicates how to stop the loop. Two loop side-by-side with no wires going from one to the other means they will run in parallel. This is dataflow:
It sounds to me like you need to do some digging into that LabVIEW manual and go through the tutorials. This fundamental concept is explained in them.
Message Edited by smercurio_fc on 05-10-2007 01:19 PM