hardest time trying to configure midi keyboard

Please help. Although I am not new to midi, I am having such a difficult time trying to configure a simple midi keyboard system setup using Sonar X1.  I am a novice musician who had been away from recording and playing for quite a number of years.  Now that I have some time to play and create, I would like to get started again.  Years ago, I was able to call the Cakewalk support center and they were kind enough to configure my setup.  It was working fine.  But recently, I must have changed something in the preference screens and can't get the music keyboard to activate any soft synths.  I could really use some help with what I need to do in getting my simple system configured.  I am trying to use a Korg Poly-800 to communicate with my HP Pavillion windows 7 system via a Tascam US-12mkII.  I watched a few videos on Sonar University, read the Sonar X1 by Scott Garrigus but I am having a lot of trouble.  Any help that can be provided will really help this old rock and roller.  Thanks.   

Is that an original Poly 800? Wow that was my first keyboard. It was nice and portable and teamed with my Roland 505 was my first live midi bass player. I think I traded a Fender Twin for it. 
 
So we will assume your using real midi via your interface. 
Make sure you have the Tascams midi ports checked in Preferences/Midi/devices/Input. 
Then you chose the Tascams midi port /OMNI as the input for the midi track. 
I know this sounds dumb, but make sure you have your midi cables connected correctly the keyboard output to to the tascam input. 
There also might be a setting in the Korg that activates midi output and chooses a channel. 
 

Thank you Cactus Music.  Your chart help me solve what was going on.  As simple as clicking on the "input echo on" icon and the sounds started playing.  Thank you.  So if I understand this correctly, does the "input echo on" mean that the signal needs to be repeated to get to the soft synth?  If that is the case, I will need to always have that button activated when using any soft synth and have it deactivated if I want to us the sound of the Poly-800.  I haven't used the sounds of the Poly-800 in a long time and only use it to be a small convenient controller for the soft synths. 
 
But you are right.  It is an original Poly-800.  I bought it new when I was still in high school and it has worked very nicely all these years.  It has gotten a lot of wear in its day and is still fun to break out and tool around. My son has been playing around with it and it sparked my renewed interest in getting back into the creative groove and recording musical ideas.   I wanted to get the music keyboard and the computer communicating properly before I connect it to a slightly larger (but still a midi dinosaur) keyboard that I used, a Korg DS-8.  With that keyboard, I will be able to take advantage of its touch sensitive ability.  The Poly-800 does not have that capability. Thanks again for your help.  
 

When using MIDI, you need a softsynth to play the notes. If wanting to use the keyboard sounds, you will either need a softsynth with those, or get them directly from the keyboard via audio connections (not MIDI). Be advised to set all volume levels to zero (I would also power off the keyboard) when making/breaking audio connections. Volumes at zero, then power on, then bring up volume slowly till you get a feel for normal levels. Power off in reverse.

If that keyboard has a VSTi (softsynth) version, you can use that with your MIDI setup now if so inclined.

Thanks to all who responded.  I am loving the program, now that I have it up and running with your help and guidance.  The Poly-800 that I use is really only used to access and control the soft synths.  The Poly-800 itself has some good sounds (albeit very dated).  But when I used it decades ago, I ran it through various pedal effects which gave it some cool depth and character.  My other board that I used was a Korg DS-8 which then controlled a Roland Soundcanvas for live performances and recording using a program called Sequencer Plus (a midi only recording program).  But with Sonar having so many great soft synths, I can keep my setup pretty simple with fewer wires. Catcus Music - I will have to download the Poly-800 soft synth for fun.  Thanks again for all your help.  Cheers!