Well, good luck then, you can format your drive 5 times, its still possible to extract info.
You can turn off your computer, I can still recover data from your RAM, yes RAM.
Please read some more on the topic before you spam with nonsense
Bartek
If the drive's blocks with relevant data have been overwritten, good luck recovering the data

Cold boot attacks on DRAMs are also getting harder with every new generation of CPUs (memory controllers).