I just run drive wiper it said something like 11 hours to complete, after a few hours I switched my pc off. Does this mean CC wipe start again to wipe from the beginning ie another 11 hours until it is wiped clean or does it start again from where it stopped?
CC is not restartable, it will begin again from the start. If you're using more than one pass overwrite, switch to Simple Overwrite one pass, this will save time and wear and tear. You might have lost some free space when you switched your pc off. If you have post back here.