ditto dude, the shub is famous for it's random resets. Next time it goes down ring VM again and ask them to send an engineer out. If they muck about send an email to
neil.berkett@virginmedia.co.uk and I can guarantee you'll get one sent out then. If you email him be calm and polite and provide the facts so they have got as much info as poss with regards to what has been happening and a timeline to work with.
It is for this reason along with many others that many of use always suggest putting the shub in modem mode and investing in a proper router (Linksys) even if it does cost you. You pay for what you get and the shub isnt worth having even when it is free.