First things first. Please name your threads more accurately (you'll likely get yelled at by a Mod soon about this), don't just name them "Help please" or "Noob question" or things of the like. An example title for this thread could be "FPSC says Free Version even after I re-enter serial in setup.ini".
Second... not sure if you realized this, but your entire post is in bold. There's no need for that. Bold should be used for emphasis on certain words, not the entire post.
Now, as for your problem, let me get this straight:
You first installed FPSC and gave it your serial. After using it a couple times it reverted to being FPSC Free? You then went into setup.ini and put your serial key in there and that didn't work? Or did it only work for another couple times?
If you are indeed putting it into the setup.ini file, I think that's incorrect. I believe you need to put it in the "userdetails.ini" file, or something similar to that. I believe it does have "user" in the name of the file, though.
There are countless other threads on here about this same matter, I'm sure they have the correct file in them. Also, I believe there is a sticky on this board about FPSC Free, and it likely has the correct file name in there, too. Check it out and see if you're messing with the right file.
[EDIT]
Looks like the sticky isn't there anymore. Or I imagined it, lol.
In any case, here's a thread that you can look at for information:
http://forum.thegamecreators.com/?m=forum_view&t=138523&b=21
The one and only,
Only those who sow the seeds of their desires will reap their benefits later.
However, I have seeds of my own to tend to. I don't have time to be someone else's watering can.