When to abandon a sphag and bag effort?

[Annika]

About 2 weeks ago, on the advice of some folks on another orchid board, I unpotted and bagged one of my phals. I got it as a gift and didn't realize, being a novice at this, that I probably should have repotted it right away. Well, I discovered that its roots were pretty much all rotted away with one or two firm (but not green) roots remaining. I soaked it in a hydrogen peroxide solution before bagging it, but didn't have any rooting compound. Well, after 2 weeks, I don't see any signs of new growth---everything is kind of blackish grey---and now the bottom leaf has yellowed and dropped off. Is it time to abandon this poor orchid to the graveyard? Advice appreciated! Thanks!