When banks stopped trusting each other in the wake of the collapse of Lehman Brothers, central banks stepped in to provide funds as long as it took to  BIS Review 75/2010  7  sort out the problems. We have acted similarly in the last month, though this time less in the interbank market but principally in the market for sovereign debt.
In both cases, however, the important point is that while central banks can calm liquidity crises, they cannot resolve solvency crises. For the banks after September 2008, this implied writing off bad loans and raising capital, either in private markets or with the help of the public authorities.