It's a dangerous business, going out your door. You step onto the road, and if you don't keep your feet, there's no telling where you might be swept off to.
--Bilbo Baggins (Lord of the Rings movie)
As the question's comments suggest - your first step is to stop and breathe. "Risks," especially as vague as you've described it, are infinite.
Have you ever seen the recent Toshiba commercials? There's one that goes along the lines of:
"This product is ready to ship, if we don't include the built-in wifi."
Manager thinks for a moment and visualizes the following scenario: Guy tries to set up the product, but his network cord doesn't reach, so he yanks really hard on it. This pulls on the cables leading to his house, causing a wide-spread power outage. A few days later, some guy, somewhere else affected by the outage, drinks from a carton of milk, but the milk is bad and turn him into a zombie. So, the decision not to include wifi starts a zombie apocalypse. "No," the manager responds, "put in the wifi." (Whew! Survival of humanity crisis averted!)
Sounds absurd, doesn't it? Unfortunately, that's what a lot of "must be prepared for every risk" is (and it's more widespread than you might think). It's called "worst first thinking" and it will drive you crazy trying to identify and plan for every possible risk that you and your family might ever encounter.
That's not to say, however, that you should just give up on all risk assessment and management, and none of it really needs software. So, here's what you could/should probably do instead, and you just need a pen and a few sheets of paper for pretty much all of it.
Come up with the things you think are risks. At the moment, just brainstorm. Take ten minutes and write down everything you can think of during that time (chance are, you'll think of most of the stuff you're likely to encounter, and at the very least, you'll identify what worries you the most).
If you want to see what other parents have encountered (you know, "the things no one told you"), then check out parenting blogs, the more humorous parenting books, or even comedians with kids. These types of resources will show you things about life in general, without the scare tactics that often come in a lot of parenting books (for an example of what I mean, check out comedian Jeff Dunham's account of his daughter walking one of their dogs).
Assess how likely these risks are of actually happening. My house could, technically, get destroyed in a hurricane, but I live in Ohio. Even when the hurricanes do actually make it here (it's not unheard of, both Fran in 1995 and Ike in 2008 hit here and did quite a bit of damage), they're not going to be the full-force hurricanes that they were when they made landfall. However, there is a pretty good chance that a storm (any non-winter storm) will spawn one or more tornadoes, and flooding isn't uncommon around here, especially in the low-land areas.
Regarding kids, there's a very small chance that someone will kidnap my son while he's out in the front yard. However, that chance is even less than the chance of being struck by lightning. The more likely scenario is that he will run out into the road and be hit by a car, or one of the neighbor kids will run into him on their bikes or while running.
Plan for the actual and most likely risks, and be reasonable about it. To continue my tornado example - figure out where you should go in the event of a tornado (the basement) and make sure everyone knows this information. When a storm is coming, make sure you know where your flashlights are, and that they have good batteries. Have a plan for what to do if the power is out for more than a few hours (for us, it was to grab the perishables and spend the weekend at grandma's, for example). If you have a basement, make sure it's water-tight (you don't need a wet basement to begin with, but when a tornado is bearing down on you, you don't want to have to worry about water, either).
Again, with the kids, your most likely dangers will be things like bookshelves or other tall furniture (usually for little kids, who like to climb), cars in the road (kids don't often think to look for cars), and rusty nails (Tetanus shots suck). Take reasonable measures to keep these most likely risks from happening, such as forbidding climbing the furniture, teaching them to look both ways before crossing the street, and to watch where they're walking (and just in general for them to be aware of their surroundings).
Find the underlying patterns. There are, obviously, a huge, huge number of risks, but, for the purposes of planning on how to deal with them if they come up, you'll find that there are a lot of patterns. For example, it doesn't really matter whether the power went out because of a storm, or if some drunk just ran their truck into your local substation. All that matters is that the power went out, and you need to act accordingly. Likewise, it doesn't matter if little Johnny stepped on a rusty nail, or Jane fell and broke her arm, or Nancy somehow caught the Bubonic Plague; the course of action is the same in all scenarios - go to the nearest emergency room to seek medical treatment. When you find these underlying patterns, you can be prepared for a lot more things without having to consciously identify and specifically prepare for them.
Realize that risk management isn't just about preventing every conceivable risk. In the IT world, we have a saying regarding security and risk management stuff - "it's not a matter of if something will happen, it's a matter of when." Or, in other words, sh*t happens. You can't bubble-wrap your kids, and you can't bubble-wrap the world. Common-sense stuff like seatbelts in the car, helmets while bike riding, awareness of your surroundings, and knowing what to do during natural disasters will take care of more than 90% of the risks that you're likely to encounter in everyday life. For the rest, well, that's what learning First Aid, keeping the emergency numbers in an easily-accessible place, and knowing where the nearest hospital and urgent care facility are come into play.
Don't be afraid to take risks (and let your kids take them). I'm not talking about playing Russian Roulette, here, but seriously, it's okay for your 5 year old to play on the swingset in your back yard. It's also okay for him to play back there without you standing over him. Could he fall off the swingset, or out of a tree? Yeah, it's possible. However, if you remove every risk out of your child's life, then s/he won't know how to handle risks, and once s/he's out from under you will likely seek out unreasonable risks to sort of compensate, completely freeze in the face of an unavoidable risk, or have no perception of risk whatsoever. None of these situations are good things. Without a perception of risk, one's more likely to engage in risky behavior; freezing in the face of an unavoidable risky situation could mean getting even more hurt; and seeking out risk...well, I think that one's a given.
Edit to add:
If you're starting a new life event (you mentioned a child starting kindergarten), then think about the typical day with the new life piece. In the case of kindergarten, you get your child up, s/he gets dressed, eats breakfast, and probably either walks or rides a bus to school. S/he then spends 3-7 or so hours (depending on if it's half or whole day), then comes home, plays, eats dinner, and goes to bed. Okay, now we have a starting place! Now, what dangers might s/he face? Well, if s/he walks, s/he might risk getting hit by a car if s/he has to cross a street. If s/he rides a bus, the bus might get into an accident. In either situation, or at school, s/he might encounter bullies.
Okay, well, you can't do anything about the bus getting into an accident, though you can make sure to teach your child to stay seating at all times while the bus is moving, and trust the bus driver to drive safely and that the "seated at all times" rule is enforced. If s/he would be walking to school, you could walk with them for a few weeks to ensure that s/he can walk the route safely (and that s/he knows the route and won't get lost), and make sure that s/he knows how to cross streets safely. For the bullies, you can teach your child to stand up for him/herself, how to avoid conflict, and how to physically defend him/herself when necessary (martial arts are great for pretty much all of this, if it's something they're interested in).