Just took the time to read what bitcoins are all about. Got to say I like the idea.
I understand most of it, except what exactly are we calculating? Hashtables creating blocks, but of what? Just useless hard to find mathematical proofs to dispatch the new coins introduced in the market randomly? If it's the case, why does powerful computer should be advantaged? Shouldn't it be randomly decided? Otherwise, does the processing power is sold for real money to medical research and stuff and it get converted to bitcoins?
Questions that should be on the Bitcoin's main page FAQ:
-Does the Bitcoin client use any processing power on idle mode? What about network usage?
-Miners of course use your processing power, but what about network usage?
I used Bitcoin client + GUIMiner (as recommended on a random pool I picked). It worked fine, but when clicking on "Stop" in GUIMiner the computer completely shut down unexpected (fans stop and everything). Bad GPU call?
I try to enter the Bitcoin client again, and all I get is a "Error loading blkindex.dat" error message. Already corrupted my data after one run? Not very fool proof. How can I resume? Will re-install loose my address and progress?
Yes, they are "useless" calculations. They will not be used for any kind of medical research. What most people fail to realize is that miners support the network. These calculations ensure that money will not be spent twice. The network needs miners and as a reward for they work, they get a few coins. The discussion here
might interest you.
The Bitcoin client does not use any relevant processing power. Network usage is high at first (until you download all the blocks), but then it is kind of low. As for your problem, I can't help. But you should be mining at a pool. To mine at a pool you don't need the Bticoin client. You only need to enter your pool credentials at the GUIMiner.
PS: If you don't have any bitcoins yet, you can reinstall your client. And mining is not "resumable". The work you have previously done does not influence the work you will do in the future. It's like a lottery. You just are throwing random guesses at something.