Isolating a MOSFET with an optoisolator
(1) Q1 MUST have a "pulldown" resistor from Q1_gate to Q1_source to turn it off when Q5 is not on. At present when Q5 is off, A5 collector floats, so Q1 gate floats, so the MOSFET Q1 could be off or on or in betwee.

(2) Q5 base needs a resistor to 4N35 output to limit LED current. You know that. 

(3) To change "sense" of operation so that Q1 is on when the button is pressed.  


Change Q5 to an NPN with collector to Q5 gate and emitter to ground,   
Change optocoupler to between Q1 base and V+12 via a resistor.





  I forget to put the resistor in the way to 4n35 but i wanna know if this circuit is ok –


As this MAY be the most important issue you MUST show your actual circuit. It is not obvious that you mean what you say there.  

As you also say  


  i forgot putting the resistor from the gate to ground,


But the 4N35 connects to Q5 base, and Q5 does not have a gate. You MUST show your complete and correct circuit.

And you say both  


  becouse the mosfet is always on
  and  
  
  when i close the button current from the r1 resistor stop flowing and when is open flows, i want the oposite effect


These are quite different things AND all the information should be edited into your question. 

____________________

Presentation matters:

To get good answers you MUST take notice of the following.
Questions which do not adhere to basic good presentation rules are more often than not also poor questions technically (a perhaps little known fact).  

Your question MAY be OK technically, or not, but its poor presentation makes it hard to read, and people will down-vote it and close it.
Arguing about this will not help you - learn to follow the basic rules. 

Do NOT use all small letters - capitalise the start of sentences.

Use I for I and not i.

Break sentences up with punctuation and add spaces between paragraphs where needed.


  so dont be so agressive if you see some typing errors,


Ignore Olin's rudeness and do not be rude in return. If you fight with Olin and similar you will lose - the moderators will put your question on hold. 

Your errors are largely not 'typing errors' but are made by choice. 

Instead of


  i had a 3d printer, the control board gets too hot, it work but it get too hot, and i want that the current flows trought the source to the mosfet and then to the hotend, i discover that if i touch the ground of the source and the ground of the hotend control board output its automaticly turns on wihtout command, so i had to use some isolator, i build this circuit, i use a 4n35 for isolating the hotend controlboard output, and then use a pnp transistor for conecting the gate from the mosfet to the 12v, i put 2 diodes to step dow the voltage to 10v, i wanna use the irf740n , i dont know if my circuit is grong or its my circuit simulator that its bougus becouse the mosfet is always on 


Do something like:


  I have a 3D printer in which the control board gets too hot.
   It works but it gets too hot, and I want that the current flows through the source to the MOSFET and then to the hotend. 
  
  I discovered that if I touch the ground of the source and the ground of the hot-end control board output it automaticly turns on without command, so I had to use an isolator.
  
  I build this circuit, using a 4N35 for isolating the hotend controlboard output,...