I'm desperate.You may think you're desperate, but you're not. Keep reading...
I'm almost 38. Start programming at 10. Spent 7 years in video game industry as programmer, project manager, CTO.
None of that matters. Today is Day 0.
I tried during 5 years to create a "startup".
You don't "create a startup". You supply solutions to other people's problems. When you do that properly, a "startup" is often the byproduct. Focus on their needs, not yours, and allow the "startup" to evolve to what it should become instead of pushing some preconceived notion.
I still have a half time job that pay the bill and give me enough time to create something.
That's great! Fantastic, in fact. You have the best of all world's: enough income, enough time, and enough connections to other things and people to supply yourself with plenty of demands to supply. You're ahead of 95% of others already. So please stop feeling "desperate" and harness the excellent position you're already in.
During these 5 years I created a game, a tool for geeks, a B2B project and lot of more things. I created some projects alone, with CEO partners, CTO partners. Each time, I have no traction, negative feedback, I demotivating and then I stop the project.
a. Focus on what someone else needs. b. Limit the number of others and needs to streamline that focus. c. Work alone as long as you can. You may surprise yourself at how much you can accomplish.
I read too much about pretotyping, MVP, lean startup, marketing.
Then stop reading and start doing. When you reach the point where you don't know how to do something that you must do, then reach for help, reading or otherwise, but not before then. Allow yourself to be pulled by your customer's demands, not pushed by what you think you should be doing.
Now I don't even know what to do.
Find a customer.
All ideas I have seems already made by someone else, and often better than I planned to do them.
That's a good thing! You want other people's great ideas. It's your execution, not their idea, that will be your key to success.
Each partners I meet seems too newbie to work with.
Then work alone and learn what you have do when you need to.
It's horrible because I have time and skills to do lot of things but nothing motivate me anymore.
That's because you're too focused on yourself, and not enough on others. Concentrate on satisfying someone else's needs by supplying something excellent. That's almost always enough motivation. You'll see.
I think all those failures killed me and now I'm lost. What a waste.
They weren't failures, but necessary learning experiences to get where you are now. Thomas Edison, Walt Disney, and Colonel Saunders all "failed" many more times than you have before they succeeded. And each one of them would tell you that those "failures" were necessary but not sufficient for success.
Take a deep breath, get rid of you're stinkin' thinkin', regroup, find a customer, and build something great. We both know you can do it. Best wishes.