Virgin Media was not formed in 2006. A pre-existing company simply changed its name. Companies House will confirm that that company records for the entity that calls itself Virgin Media go back far earlier than 2006.
It was, and will ever be, a re-branding exercise. It uses the Virgin brand under licence. Underneath it is a company formed from the merger of NTL and Telewest.
Companies do not often cease to exist - you will find, if you were to look hard enough, that most if not all of the legacy companies still exist as subsidiaries. Furthermore the company we now call Virgin Media is legally liable for the historical activities of those subsidiaries.
Virgin - or rather, NTL and Telewest, many of whose senior staff are still around AFAIK - did run out of money. NTL in particular was in Chapter 11 Bankruptcy protection in the USA not so many years ago. They ran out of money because they were liable for the massive debts of the telcos they bought up.