why i cant loggin

hi , i need to know why i cant loggin my avatar, anyfriends say me she is online but it's not me

Do you see an error message when you try to log in? What does it way?

If you appear to be logged in to your friends but aren't really there, they can try to send you an IM or pay you some tiny amount (1L will do if that works at all). If those don't work, you can try to log in at a different location. If that still doesn't work, you will need to contact LL support (mainland) or the sim owner (private estate) and ask them to restart the region.

Other alternative: does anyone else know your password?

Your avatar probably "ghosted" when you logged out at your last location. This just happens sometimes, no idea how. Try logging in "at home" if that wasn't your last location, or log in to a completely random location using some SLUrl. If this still doesn't resolve your problem, go to the Second Life support page and file a ticket. Once a Linden gets to it (...), he or she can resolve it in a matter of minutes.

If your friend sees your avatar there still, yes, chances are you are ghosted. SL is confused about your state, and thinks you're still logged in, so its not allowing what it thinks is a hacker trying to take you over.

- To fix it, have your friend contact the owner of the place your avatar is still at. About land will tell you who this is, as well as double clicking on the thing at center top of the screen that says the location name and coordinates.

Have her tell that person that you are ghosted on their property, and they can put in for a reset.

Now a question to people who've had to deal with this in past: Could it be fixed in other ways? Perhaps banning the person from the parcel to force SL to do something with them, and in the process realize they are not logged in?
(obviously you'd revoke the ban a moment later... but would it work?)

just kicking from the land is sometimes enough, if kicking doesn't, banning probably won't too, either of these would be problem if it's your own land too.

I don't know about a ban. Sometimes sending the affected avatar an IM or paying them L$1 will encourage the system to log the person out. I've never tried banning or kicking from the parcel. I'll have to keep it in mind...