700k aint really much but used rightly it can become much. But seing as you is a greenhorn, i suggest as follows.
1. put it in stocks for now. buy on the floor thru a broker, a PO denies you access to the funds for like 6 months.
this way you wiil be sure to have the money intact, appreciating and accessible.
2. Do your homework, catch a vision. What do you love to do? do you have a skill, talent, knowledge or experience in something?
Anything in which you can beat your chest. Focus on that area - that's your competency.
3. Do a market research in that area e.g. what needs exist? what can you imrove on? how big is the market? is it accessible?
4. Write up a biz. plan (make sure to cover every aspect of the business)
5. Write down your action plan, break it into 24hr, weekly & monthly goals. (bite-sized, i call it)
6. Just Do It(Trust NIKE). or Go Start Something (a la MTN).
Let me know if you still need help. Biz. consulting is what i do.

I've always said it, that no knowlegde is wasted. And everyone has something he knows that can get him to where he's going. Every dog has its day. Just know what is your area of strength and competency, it may be a talent, skill, knowledge, or experience in something. You just know you are good at this thing.
Once you've discovered what it is, i can tell you what to do with it and how it can serve you. You can create your own opportunities from that thing, even start a business along that line. Believe in yourself.