Settings:
APN: myq
all others blank
I cannot use the internet abroad with prepaid Q.
I choose networks manually as mentioned here
http://www.wind.gr/en/q/support/services/roaming/ because data roaming is not possible on all networks.
I can call, receive calls, send and receive sms.
I tried in the Netherlands, Germany and Hungary.
I tried apn myq.gr but that doesn't work neither.