I want to put my Packard Bell Easynote BG45-U-300 up for sale on Ebay as it's rubbish - it still works but it overheats, the charger connection is shot to bits and it's super slow. I obviously understand that I need to wipe everything off it (I've already transferred all my personal documents / music / photos to my new laptop) but I know that 4 years worth of deleted items etc will still be sitting there and I don't know how to wipe them. I've spent hours googling it and all I keep reading is that I need to use a specific disk to re-format it. My issue is that it's a notebook and doesn't have a CD drive so I've hit a bit of a brick wall. I really don't want to take it to a computer shop to spend money getting it wiped otherwise I may as well chuck it in the bin but I'd at least try to make a bit of money out of it!
So my question is:
How do I wipe my laptop without having to use a disk?