Bitcoin spontaneously refusing to start at all

[Reacon]

I've had this problem twice now, and I'm stuck with redownloading the entire block chain again.

Basically, sometimes when I start Bitcoin's official application up, it will begin to start, and then the process will end. I countered this last time by moving my blkindex.dat, but that requires me to retrieve the entire block chain.

Is there any way to prevent or fix this? It is a really big annoyance.