TS1453 Apple TV doesn't show up in my iTunes. I've done all the troubleshooting steps, updated all software, restarted Apple TV, wireless router and computer. Devices doesn't show up at all in my sidebar.Apple TV doesn't show up in preferences

Question

Help.  My Apple TV won't sync with my computer.  I've done all the troubleshooting tips, but Apple TV doesn't show up in my Preferences under devices.  
2. Reconnect Apple TV to iTunes.
Choose iTunes > Preferences (Mac) or Edit > Preferences (Windows), click Apple TV, and make sure "Look for Apple TVs" is selected.
I see no option to select "look for Apple TV's" in Preferences, and there is no device list at all in my sidebar.
3. If Firewall is on in Mac OS X (in the Sharing pane of System Preferences), make sure iTunes Music Sharing is selected.
There is no option to select iTunes Music Sharing in my System Preferences - see screenshot
I've updated all software, restarted Apple TV, my wireless router, and my computer.  Both my computer and the Apple TV are connected to the same wireless network and both are operating properly.  They just wont connect to each other.
Does anyone have any suggestions?

Answer 1

FIRSTLY: bookmark following for further reference (it describes basic setup, both to link for syncing and to stream - from any computer.)
Apple TV (1st generation): Differences between syncing and streaming" )
Now as to your problem: If you check under "Computers" in the "Settings" menu you will most likely see the name of your iTunes library Greyed out. IF that's the case, you'll basically need to re-setup your ATV., you can do so as follows (instructions are intentionally over described, but basically your disconnecting then reconnecting your ATV1. Downside (which seems to come with all methods is that you'll have to resync all your media)
**A (not ideal but effective solution)
If ATV 1 had been working but suddenly 'disappeared" from iTunes sidebar
The following solution will almost surely work  to regain your ability to Sync:
QUIT iTunes
Select "Computers" from "Settings" Menu.
Select your "greyed out" iTunes library.
This will bring up a window named "Disconnect from iTunes"
You're now given the choice to Cancel, or disconnect. WITH THE WARNING that if you disconnect any  content synced with iTunes, will be erased. (in fact it will be removed from your ATV but not your computer)
Assuming ALL of your media IS on your computer, Go ahead and disconnect.
Follow instructions in the Apple doc above about setting up your ATV as a paired computer.
After you ATV gen1 reappears in the sidebar. Reset all your desired syncing preferences,
Begin syncing.
All will be fine again, (at least till the next time this occurs.) I've had to do this twice this year.
ALTERNATELY:
SHARING (a QUICKER, less destructive TEMPORARY solution (if you just want to play your media now)
You CAN set your computer to Share by following instructions in the same doc under the heading:
"How to connect to a shared computer"
HOWEVER, this will not allow you to sync info.
I've read alternate solutions on this board, one involved changing the name of your iTunes Library etc... you may wish to try this first (if it applies) https://discussions.apple.com/message/17943841?ac_cid=142432#17943841
What I'd like to know: What causes this problem...  I'm suspecting iTunes updates, or any iTunes database issues or crashes. Or maybe too many visitors connecting to your other Apple devices (ATV 2 for example) or heck the weather in Guatemala...