How do I move my iPhone to a new iTunes installation?

Question

Hi folks,
I have a new Windows 7 computer and want to sync my iPhone with it, but iTunes says it's going to delete all of my data. My old computer that I used to sync with is gone; the drive has been reformatted.
I don't care about the music on the phone; I have all of that on my server. However, I'm worried sick about my apps and the data stored within them!! I have years worth of life data, journals, etc, in apps on this phone. How do I tell iTunes, "This is my new computer now; back up and sync here from now on?"
Here's what I've done so far:
1. I authorized the new iTunes installation with my iTunes account.
2. I right-clicked on the phone within iTunes and selected "Transfer Purchases." It appeared to work, said it was copying all of my apps. But when I go to the Apps tab and click "Sync Apps", it tells me it's going to replace all of the apps on my phone with the apps in iTunes. However, I only see two (out of dozens) of my apps there! Did "Transfer Purchases" not do what I expected it to? How can I fix this?
Thank you!

Answer 1

It has always been very basic to always maintain a backup copy of your computer for just such an occasion.
Use your backup copy to put everything back.
The iphone will sync pics and itunes content with one and only one computer at a time.  If you sync to another, it will indeed erase the current content and replace with content from the new computer.
Also if you sync contacts/calendars to a blank computer, they will be erased as well.  Another reason a backup is critical.
If you have failed to maintain a backup ( not good)then, transfer purchases will transfer itunes purchases.  Make sure you have authorized the computer for your itunes account(s).
About iTunes Store authorization and deauthorization
Backup your iphone:
Backing up, updating, and restoring iPad, iPod touch, and iPhone software
Enter one unique contact and calendar entry on the new computer.  When you first sync you should get the option to merge the data.
Than make a backup copy of your computer and always maintain it.