URGENT - How do I upgrade another iphone on another PC?

[ivenus]

Okay so I need to upgrade a iphone 3g to iOS4 on my computer; it doesnt have any of the music/contact/backup on it. Is it true if i backup the iphone to my computer and do the sync it will still hold all the contacts/text messages/ system settings in the backup?

 

[BKM72]

You can do a back-up restore as a second device. Meaning, you have to retitle the backup.

I save my girlfriends daughters ipod on my computer (Win 7). Just be careful to specify that its a new device in the back up section. Your allowed 5 devices (I think)