My BB just did this. It's called Black Berry Coma and if you google it you'll find that BB's do this because of a lot of different reasons from exposing it to water to letting the battery run down too far and turning off the phone, which is how my BB went into its coma.
One night I turned off the phone to save on the battery life because I forgot my charger out of town and when I went to charge it up and turn it on again, all that happened is that the red light flashed solid.
I kept trying and read all these things on the Internet about how people got their phones to turn on. I tried them all. The one that worked the best was warming up the battery in my hand and putting it back in, but that still didn't work.
One person on the Internet said they just left the phone alone for a few days and then it finally turned on and that's what happened to me.
The BB has a bug. The worst thing I find to ever do is turn off my BB. Doing a battery pull is good. But turning off the phone itself seems to create problems.