Download the correct .iso (Windows 7 Home Premium SP1 x64) and follow the instructions to create a bootable USB or DVD (download links and follow my instructions are here). Once you have the bootable USB/DVD and your product key follow my wiki A Clean Install of Windows 7. Note you will have to activate via phone. A Clean Install of Windows 7 gives the information on phone activation (Step 11). You can alternatively request a Reinstallation DVD which is also mentioned in detail in A Clean Install of Windows 7 (Step 3).
Ok so.. a couple days ago my hard drive just died on me, unfortunately i did not save anything or use the backup option :( I took my laptop (a Dell Inspiron 1803 which came with Windows 7 Home Premium 64 bit) to a family friend that fixes computers, since I didnt have my windows 7 disk and he didn't have one either he installed windows vista home premium 64 bit on it (which honeslty sucks no offense to anyone that owns it) I really want to have windows 7 back on my computer but I dont have my CD although I do have my product key sticker. Is there anyway I can ask for one? I just called dell and since I'm out of my warranty the only way they can help me is if I pay for their tech support, which I wouldnt mind doing if I wasnt broke atm. I don't mind having to pay like $20 to get  a replacement. I already asked around, none of my friends have windows 7, is there anything else I can do? If so where? A link or number would be appreciated or if there was a way to some how get back to factory settings that would be better
From Windows 7 to Vista back to windows 7?