Hi, my problems are actually more complex than what is written in the topic, pls take your time to read, and hope to hear some solutions from experts here.

I have a old iphone (name it A), previously synced with my old laptop, which has since been damaged.

I bought a laptop from a friend, he has previously synced his iphone (B) with this laptop.

i have just bought a 3G iphone (C), and trying to sync my old iphone A to this laptop, so that i can transfer the info to my new iphone. But when i connect A, it recognises it as B. i try to sync it. But when i plug in my C to restore from previous sync, my friend's B info got transfered into my new B instead.

I tried deleting all his contacts from outlook etc, and even reinstall itunes, but everytime i plug A in, it thinks its B.

How do i completely remove B from my laptop. presumably i can, can i synced it to A and subsequently to C? pls note that A has not been synced to this laptop before. or any better solution to transfer the contacts at least?

this is what i am trying to do:

Remove all traces of B --->Sync A into laptop (backup)-->Sync info from laptop to C

what u can do is try syncing with Windows Address Book or Mac Address Book........

did you try to delete the sync-history from itunes, then sync with A and then try sync with C again?

As far as I understand, you are on a Windows-PC.
I usually do not recommend to restore back data from an old iPhone (like a 2G one with firmware 1.X) to a new one. You see lots of users here, getting into trouble doing that.

Most users want to use the restore backup to get back SMS, call history or other data.

Here is where a user (D) comes into the game, he should have a Macintosh. On your computer (A) goto (if Vista, on XP it's bit different)
c:\users\<username>\AppData\Roaming\AppleComputer\ MobileSync\Backup\<long-name>

Copy the complete directory backup including the directories (with long numbers) on an external drive or USB stick. On the Mac of user D put the directory with the long number as dir name into
~/Library/Application Support/MobileSync/Backup

Get Erica Sadun's mdhelper here
http://ericasadun.com/ftp/Macintosh/...-universal.zip
unzip it on the Macs Desktop ans start the application Terminal (in /Applications/Utilities). Then type:
cd Desktop
chmod 755 mdhelper
./mdhelper -C .*

You will find a folder on the Macs Desktop containing all settings, extracted from the backup file of your Windows PC. Like sms.dbm AddressBook.sqlitedb, ...., pictures, settings etc.

On your PC SFTP into your new iPhone 3G (should be jailbroken and have SSH on it)
goto /private/var/mobile/Library/ and start replacing the files.

I know this is really a detour but will work if you get stucked with the other solutions