I have a Yamaha MG10XU mixxer
 

 
i plug in 7/8 my keyboard Yamaha s970
 
in channel 1 I plug my mic audio technica 4040
 
Now in sonar I want to track for each one
 
So track one for my mic only and track 2 for my keyboard!
 
And both recorded at the same time ?

Yes, you can do that.
Are you using an audio interface other than the Yamaha? If not, have you installed the Steinberg ASIO driver for the mixer?
http://faq.yamaha.com/us/en/article/live_sound/mixers/analog-mixers/mg_xu_model/mg10xu/10780/8675
If you use the Yamaha mixer as your audio interface, you will only be able to record 2 tracks at 1 time, which is certainly enough for your purposes,

Yes I do use the Yamaha as interface. No i'm in sonar how can I use tow track at the same time ?

In SONAR, in the Track Pane, choose the inputs for each track you want to record on, as in track 1 Input Yamaha Right; track 2 Input Yamaha Left. Arm both tracks to record, play and sing to set the recording levels. Once your levels are set, click the Record button.
Have fun!

Connect the mixer to the PC via USB. Pan the mic all the way left and the keyboard all the way right. Set the input for the mic track to the left channel of the Yamaha (click "Input" in the control pane of the track. The Yamaha should show up there.) Set the input for the keyboard track to the right channel of the Yamaha.
 
Try to make  more descriptive title for your posts. "Help me out" doesn't really describe your need.

it work only if i turn the fx return off in my mixer !! But i need the fix what could i do. sorry i'm bad with english

musaed
it work only if i turn the fx return off in my mixer !! But i need the fix what could i do. sorry i'm bad with english

Add the effect after recording by right-clicking in the FX bin and selecting the effect you want.
Also, Cakewalk doesn't ever really close threads unless there are numerous TOS violations in it. The only way to get rid of a thread is to stop posting in it.
Oops.