STB is set top box, i.e. getting your broadband through the same box as yer TV
Not a clue whether it will be OK for 10meg, but VM will want to replace it as they seem to be standardising on the 256 modem.
VM customer services are 0845 454 1111 from a non-VM line, and technical support are the same. Or try the newsgroups at
http://www.virginmedia.com/help/cable/newsgroups/