I erased unused/free space and at the end got am message informing me that it had completed albeit with errors. I checked the log. Some are in red and are classed as Error, whilst others are in black and classed as Information. I have had a quick glance through these (it looks like there could be thousands) and they all start with '...did not have its cluster tips erased'. Is this anything to worry about or is it normal? I want to sell my pc you see and just wanted to know if it erased all my data or not?