Can't sync after restore from backup (iPhone 5)

[windbrand]

I'm trying to switch iPhone 5's with another person, because she likes white, and I have a white one. We need to swap all content on our phones to each other. Here is what I did:
- Backed up her phone on her computer, mine on my computer (backed onto computer so it's the full backup)
- Plugged her phone into my computer, select restore from my backup
- After restore, entering wifi password, account password, etc, all my contacts/messages transfered over, but the apps are all her apps. None of my apps on my phone transferred over despite being restored from a full backup
- I connect it to iTunes, and clicked sync so that all my apps are installed onto the phone, nothing installs when I click sync. All it does is say "determining apps to sync" then just stops there. No error messages or anything. Not only can I not sync apps, but not even music/videos will sync
Anyone knows what's going on here?
Once again congratulations to Apple for making everything much more complicated than it has to.

 

[bloutrein]

After restore, entering wifi password, account password, etc, all my contacts/messages transfered over, but the apps are all her apps. None of my apps on my phone transferred over despite being restored from a full backup

This is odd. If you restored the black iphone from a backup of the white, the apps restored should be from the white (i.e. yours) and not the black device.

On the black iphone, go to Settings > iTunes and App Stores and make sure that it is your account and not your friend's account.

Also, when in iTunes, make sure that you connect your iPhone, navigate to the "Apps" tab and the "Sync apps" option is checked. Of course, ensure that the apps which appear in your iTunes library are actually yours and not your friends.

Finally sync the black iPhone once again with your iTunes library and accept all warning messages.