Hey CH my installation cds are on the way so I can have vista and ubuntu on my new laptop!

So I got this old computer, but it has viruses and stuff.A friend of mine wants a computer and hes offered $200 for the old 2001 dell dimension computer, lol he is a retard because I bought it for less and he could get one for free I bet, but he likes it because he thinks the box is pretty.So I want to wipe the hard DRIVE and clear all the data completely, then reinstall windows, how would I do this?Is there some magic cd I can get for free and then boot it up and it erase everything?Do I reformat it or something?What is the best option for free?A FORMAT and reinstall is ok if you have no personal data on it and just want to clear of any viruses and such.
But if you want to be fairly certain he isn't going to recover any of your old data, I suggest you wipe the drive with something like DBAN. You burn it to a CD or install it on a floppy and boot the computer with it. It has different wiping modes depending on how secure you want it. After it's done, no recovery software in the world is going to find anything on that drive.
That being said the data can still, in theory, be recovered. But it would require specialist equipment and knowledge that isn't available to any regular user. So if you're storing government secrets on it (or wear a hat made of tinfoil) I would recommend you incinerate the drive or something to that effect. Otherwise DBAN using a medium/high setting should suffice.type in LOW level format on google and download the programme. Easy! When you next turn the computer on have the windows cd ALREADY in and it'll START the install - but you'll have to create a partition on the hard drive, bu the windows set up will guide you through it.....Alright thanks, I actually was looking at that earlier and found a tutorial on irongeek.Did "autonuke" and its going slow, but thats probably because this computer is a piece of crap.I cant believe Im getting 200$$ I mean my grandparents get recycled computers better than the one Im selling, this is so sweet thanks!