Logic Pro not working right: HELP!!!!!!!

Question

Logic Pro is no longer sending audio signals to the mixer. The Output display is no longer available in the Mixer. Do I need to do a major reinstall of Logic from scratch?
This was not my initial problem, but developed as I tried to "fix" a different one. The following is a history of what I did with ensuing problems noted.
1) My external keyboard (Roland U-20) was no longer available in the arrange options when I created a track. (initial problem)
2) I went into the Environment and discovered it was no longer in that window.
3) I went to Audio Midi Setup and noticed it was there.
4. I imported an older environment set up. It looked OK so I then also imported this into my Empty Project Template, saved it, and went back to the initial project.
5. When I tried to play a sound from the Roland, it was not coming out the right speaker, although the correct "instrument" was there. The sound on the left speaker was very distorted.
6. I went into the UNDO section and went back. The arrange window looked like a mess with many crossed out outputs in the tracks, instead of the names of the original tracks. The environment window no longer had the Roland.
7. When opening my original piece, I then noticed that the mouse editing control buttons on the top right were altered -- instead of 3 buttons, there are now only 2. I reopened the empty Project and found the same.
8. I deleted my empty Project template.
9. In the original project, I noticed that the mixer's output buttons are no longer available. No sound at all coming out of Logic to my Firewire.
10. I opened a different template. Same thing.
11. I noticed that Logic saw me touching the keyboard, and then I tried to see if it would record MIDI data. Message: Record drive/partition "MPC12" not found.
10. Tested both i-Tunes and Garageband which both give me correct audio.
11. I went back into Time Machine and replaced Logic Pro with yesterday's application.
12. Problem persists.
13. I deleted any logic plist. I could find. Reopened Logic. The computer asked me to reregister. After doing so, the software still had not changed.
14. Rebooted the computer. No change.
15. Totally frustrated. This message sent.
Thanks for any help.

Answer 1

Not at all. Everything has been working fine for months until I did this thing today where I was trying to get my arrange window sequencing to connect with the sounds in my U-20.
It seems now that my digital audio track is working again but the output and master are not in the Mixer windows. I can not hear the digital instruments that come with Logic when playing through the sequencer. However, I am noting that if I create a separate window with the mixer, and I click on one of the virtual instruments, then touch the keyboard, a sound does come up.
So:
1) How do I get the software to create both an output and a master control?
2) How do I get the software to have three mouse control buttons for the top left of all the editing windows (arrange, score, piano roll, sample editor)?