i`m using w880i. the problem is i cannot use 3g. i go to setting-mobilenetworks-GSM/3Gnetwork then i`m choose gsm and 3g no change still at gsm only. how can i change that

Your network operator doesn't support 3G.

my network operator support 3G. there is problem with the phone

Yes, so contact your network to find out whats wrong.

I would suggest its just a simple case of the network hasnt enabled 3g on your sim card or anything along those lines