about: ipod to new itunes/computer (http://www.ipodtocomputertransfers.com/how-to-copy-itouch-songs-to-new-computer.html)
You can use cucusoft ipod to computer transfer to copy your iPod music back to computer, this will help a lot when you erased your music on PC.
Yes, but if you sync your iPod with that computer, the CD will be erased from your iPod, so I would recommend leaving the CD on iTunes.
no. everything from your iPod will be erased, but your itunes will stay the same, so when you sync it again, everything will be on your iPod again
Plain and simple you cant
No
A new version of iTunes only updates the iTunes software and does not touch your music/movies library.
Updates to the iTunes software only affect the iTunes application and does not touch your music library.
Yes u can but all of your songs, apps, and itunes store info will be erased and you will have the same account and songs as the others computer. In other words you lose your stuff but get there stuff.
Yes, but the next time you sync your iPod with iTunes they will be erased from your iPod.
Reinstall Itunes
No once you have already downloaded stuff on one computer to your iPod Touch then it is considered the authorized computer for the touch. If you go to another computer all the memory you have now from the old computer will be erased.
Then just sync your iPod to iTunes if it is on your computer. Select the app and sync your iPod (be prepared if it is going to back-up your iPod, which may take a while depending on the content on your iPod).