hi guys, need help with this:

my wife has a 16g 3gs and her issue is this. one time she sync her iphone to another computer (not hers) to backup some stuff due to emergency, never had a need to sync with her own personal PC. so now she got a new laptop n she want to to sync with it but the iphone is still sync to the above mentioned computer. how ah? she afraid she lose her contacts and sms.