Ok,, so just to be 10000000% sure, I'm going to export my .dat file, hide it on a few usb keys, then delete my bitcoin wallet, and write over my drive. There is no chance I will lose my btc....right? Right, ,this has been confirmed but I'm still nervous about it!!!
I'd check your wallet.dat isn't corrupted and works in another client before you rely on it as a backup.