Hi guys, I recently got a htc desire, got it unlocked so i can use my o2 sim in it. my question is, i cant access the internet on it.. ive been reading this stuff about 3g sims, the o2 sim ive had for about 6 years now.. its the old sims. would this be why im unable to connect to the internet? and what exactly does the term '3g' mean? also i seem to have the sim card icon (with an exclamation mark) in the top left corner of my phone and when i click on it, it says my sim card is full... but somewhere else i've seen that this icon means 'no sim installed'?? many thanks.