Is my password to enter S2 the same as my log in password on web site?

yes

but to unlock S2 you must pay for it first

I paid but somthing is wrong because im see demo racer.

Actually, it isnt the same.

You unlock S2 with your GAMEpassword, but you register at forum or lfs.net account with your WEBpassword.

At least I think it was like this.

Quote from zeugnimod :

At least I think it was like this.

it is
but also make sure u use the correct login name

Its been two days with S2 and it keeps saying user name not found.I know my user name is right.

It would say S2 on the forum as well. For some reason it hasn't gone through. How did you pay?

Quote from gchisholm :

Its been two days with S2 and it keeps saying user name not found.I know my user name is right.

When you login to the LFS website (www.liveforspeed.com) does it say you are S2 licensed? Have you set a GAMEpassword?

If you are sure on both counts, I suggest contacting the LFS team directly, as its likely to be a payment issue; http://www.liveforspeed.net/?page=mailus