the game is already running

Last night I was playing on a server and I decided to go to one of my worlds ... but when I tried to open them I always took the main menu. I closed the game thinking that it had been bugged but when I opened the launcher and gave it to play, the image message came out. This happens to me in both vanilla and forge. I do not know what to do and I do not have another game started. I have java 8.0.1310.11 and windows 10, I have 8 gigs of ram and that I know minecraft only needs 2. Help me please.
here they have the error in English:
-You have already logged into Minecraft with this user. Please keep in mind that you can only access one Minecraft world per user at the same time.
-Minecraft is already running in this game directory. Starting it again could cause malfunctions or damage your saved data. To solve this, create a new launch option and edit it to run in a different game directory.
We are not responsible for any problem if you choose to ignore this message. Do you want to start the game anyway?

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