Sync ipod using backup from different computer

Question

I have a computer (running windows 7 32-bit, if that info is needed) which is the only computer I would sync my ipod touch with (4th gen, 32GB, running latest stable iOS). I recently did a wipe and reload on my computer, reinstalled iTunes, and added back all my apps, music, etc. I also copied all my old sync files from the backup (because I was smart and copied my C: drive to an external hard drive first before the wipe and reload) from the external hard drive to the C:\Users\Derek\AppData\Roaming\Apple Computer\MobileSync\Backup folder on the computer where they should be. I can even see them in iTunes>Edit>Preferences>Devices>Device backups where they should be (see screenshot: http://goo.gl/XFgn7). But every time I connect my ipod touch to my computer, I get this warning (see screenshot: http://goo.gl/xZQjW).
My question is thus: If I click "Erase and Sync" on the warning dialog, will this act like a regular sync, or will it get rid of the apps and organizing system I have on my ipod and replace them with the ones on my computer?
AND
If the result will be replacing the organization system I have already set up on my ipod, how do I tell iTunes to sync from the old backup?

Answer 1

Make a copy of the backup that you made and place it in a safe place like in My Documents. The backup is loated:
Windows XP:\Documents and Settings\(username)\Application Data\Apple Computer\MobileSync\Backup\
Note: To quickly access the Application Data folder, click Start, and choose Run. Type %appdata% and click OK.
Windows Vista and Windows 7:\Users\(username)\AppData\Roaming\Apple Computer\MobileSync\Backup\
Note: To quickly access the AppData folder, click Start. In the search bar, type %appdata% and press theReturn key.
Then let iTunes erase and sync the iPod.
If necessary, restore the iPod from that backup .