[Work done]

I'm familiar with the mathematic principles and computer technology behind bitcoin. However, even with reading alot of the beginner's topics and other forums and such, I'm still left with a couple questions about the implementation of the currency.

A few questions:

1. Work done: I understand that my computer (mining at 250 Mhash/s) is chugging away to find a nonce for the hashing algorithm that yeilds a solution that fits in the current difficulty level. However my question is: As I watch the block count go up on the bitcoin client, does my computer have to start from scratch each time?? Or am I still working to find one of the predicted 2016 (or whatever it is) blocks for the current difficulty level?

2. "Accepted": What is a Difficulty 1 hash? And when my computer "finds" one, is it a solution to a block that wasn't under the difficulty target, Or is it some other incremental calculation?

3. Remembering: Does my solo miner remember the work it has done if I close it or my computer turns off but I get it back to work within a reasonable timeframe and before the difficulty level goes up?? I ask because the "accepted" number resets each time..

Thanks for reading.. I would greatly appreciate someone clearing this up for me as alot of this seems to be assumed knowledge almost everywhere i read..

If i've missed the obvious answers in some thread i missed, please direct me.

Thank you very much fellow miners.