my computer has a little problem: it resets almost everyday, at least once, with no obviously reason.
Did you recently upgrade memory? Sometimes it is something like incompatible memory that can cause this. Or other hardware issues.
Those types of issues are tough to resolve.
When I delete blk* I can start it again but everything starts from scratch
The bitcoin.org client uses BDB and it is a database that has the ability to recover from crashes. There are BDB databases other than blk*, there is also wallet.dat and peers.dat. If you don't yet have any funds on your wallet, then you can wipe the entire bitcoin directory and have it try from a completely clean, known state.
I had to stop to use the main client, but I want to use it because I know the main client is the best for the network p2p.
Running the full blockchain client isn't for everyone, but if you want to keep at it you probably want to resolve the once-a-day system crash issue first.
The next version of the bitcoin.org client uses a different storage system (LevelDB). I haven't learned up on it yet to know if it might function better in an environment where system crashes are frequent so I can't say if this situation you find yourself in would still occur or not. What I do know is that with the next version if you did need to wipe the blockchain and pull a fresh one, doing so is something measured in minutes (e.g. 250 minutes maybe) versus days.
