Did that actually fix it for you? I had exactly the same thing happening, intermittent trouble writting over a period of time, a reinstall, and later, that white screen of death.
I booted the Sansa firmware by holding down the RWD button, but that only goes for a little while and then it says "writing" and it hangs. Tried it many times, hoping something might change but I can find a way around it. I hope it isn't bricked, It is only about 6 months old, but I am already looking around for a new one, anything but iPod and anything but sansa.