Not really. The question wasn't directed at me but I'll take a stab at it. If looked at dispassionately Glass-Steagall would have done very little if anything to avoid the crash.
AIG, Bear Stearns, Fannie Mae and Freddie Mac, Lehman Brothers, Merrill Lynch, none of them would have come under the authority of the Act - their problems came from investments in residential mortgages and residential mortgage-backed securities. Lehman Brothers, Merrill Lynch, Bear Stearns, Goldman Sachs, none of them were parts of or tied to commercial banks. Even Obama has stated that "there is not evidence that having Glass-Steagall in place would somehow change the dynamic." Elizabeth Warren, she of the 21st Century Glass-Steagall Act, when asked in a New York Times interview whether the financial crisis or JPMorgan's $2 billion trading loss could have been prevented if Glass-Steagall was still in place responded that "The answer is probably 'No' to both." She's admitted that even though it wouldn't have done anything, because this myth has grown up around it and that it has name recognition that it's an easy issue for the public to understand and "you can build public attention behind [it]." It's basically a case of trying to get your foot in the door with this piece of regulation and then hopefully expand upon it afterwards.
Looking at the timeline of events the first to go was Bear Stearns, an investment bank with nothing to do with commercial banking, and then Lehman Brothers which was again an investment bank so neither covered under the Act. Third in line was Merril Lynch which again had pretty much zero links to commercial actions so again not affected by the Act. AIG was an insurance company so no luck there either, likewise Fanny Mae and Freddie Mac. Then we come to the actual commercial banks. Bank of America did lose some money due to investment banking and trading but the real body blow came from buying the subprime lender Countrywide Financial. Wachovia's problems also mostly came from buying a mortgage lender in the form of Golden West which ended up bringing a crapload of bad loans with it, both of which were perfectly legal under the Act. Citigroup is the one main example of where it might have actually changed things since it caused its problems by making bad loans and buying up large numbers of CDOs. The Act would have prevented it from racking up the trading losses and stopped it growing so recklessly. Citigroup however only went down when Bear Stearns, Lehman Brothers, A.I.G., Fannie Mae and Freddie Mac had already either imploded or were right about to implode with the markets being complete carnage so it could have possibly survived if not for that as well. I'll leave it up to those more skilled at economics than myself to argue that debate.
What caused the crash was the ability to securitise the mortgage debts and move them off the banks balance sheets by selling them to investors at a profit. It meant they didn't have to be too picky or do their due diligence since they were just going to be sold straight on. Why waste the time and money when the housing market is going up like a rocket, better to simply pile them high, bundle them together and then shove the investments out the door to hungry investors. And these are the commercial/retail banks I'm talking about not the investment ones. Before when they mostly kept the mortgages and made their profits from them they were bound to be more careful, when they found out that they could make more money from creating these investments and selling them then that was the start of things. Throw in a housing market that had quite literally gone insane, in part thanks to the symbiotic relationship to this, and a whole bunch of investors that were too enthusiastic to look at the underlying figures and realise that they were shit and you've got your perfect storm.