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!!!
Well dataforensics is very complicated. Sometimes people tell you they can recover everything no matter what you do, but i doubt that. The most realistic information about recovering data I read was: 75% chance to recover a single bit (if overwritten once with random data). So to get a single 7-bit ascii letter right you must have those 7 bits correct, chance for that is .75^7 = 13%. Your wallet.dat has probably >1kb so the chances are very slim to recover those data.
If I may suggest another option: Create a new wallet first and transfer the BTC there, that way you dont have to trust anything or anyone. You might have to pay transactionfees though. But you are 100% sure that your old wallet is empty and you dont have to care if someone can restore it. On the other hand you seem to have some kind of backup in mind (since you are using 3 usb sticks)