3 Mobile USB Internet Won't Connect Anymore

I recently bought a 3 mobile usb internet dongle & to start with it wouldnt work at all.

It kept saying connected but no web pages would show up & i couldnt get on msn either.
After a few days of messing about with internet options etc, i got it to work (but only after creating a new user account).

Now its went & messed up again
I created another new user account & its working :/

Any one any idea how to solve this ?
Ive had absolutely no help from 3 mobile.
I dont want to have to create a new user account every time it messes up & even when i do create a new account, it doesnt always work.

Cheers for any help i get guys =]