Wiping the hard drive completely

[zacklovesmac]

I want to completely wipe the hard drive of my current dell inspiron and reinstall windows 7. Firstly, how do I wipe the hard drive and secondly, I don't want to buy or steal windows 7 so how do I keep windows 7

 

[USAFRet]

Windows 7. Do you have a current, valid activation key?

 

[zacklovesmac]

No, I bought this computer ready with windows 7