03-04-2011 10:34 AM
Well, there doesn't appear to be any way with ACT! as it is to stop someone from changing the probability value after the fact, you can at least set it to default to 100%.
Create a new Sales Process, if you have more than one process, name it in such a way that it's name will always be first alphabetically. This will make ACT! select it as the default upon creating a new opportunity. Only put 1 stage in the process and make it's probability value 100.