I have and still continue to receive a large amount of emails or PMs asking me about clean installs using upgrade media and the legality. If you want the facts please look here:
 
http://blogs.zdnet.com/Bott/?p=1505&tag=nl.e539

As long as you have Windows 2000 / XP / Vista installed on your machine...there is one sure fire way to install clean.  I have done it and have helped two or three others do exactly the same thing.  Make sure to back up ANY data that you do not want to lose.

1.  Put the Windows 7 Upgrade DVD in your DVD and reboot your machine
2.  Hit any key when prompted to do so to boot from DVD
3.  Start the Windows 7 Installation.  Mind you that once Windows installer has determined that an eligible OS is on your drive...it will begin loading files
4.  When asked...choose INSTALL
5.  You will be prompted with TWO options...Upgrade or Custom...choose CUSTOM
6.  Follow the prompts and when asked what drive to install on...it will show your C drive and what capacity is left.  Choose Disc options...and choose FORMAT.  This will make Windows 7 quick format your drive and wipe everything before the install.  Mind you...Windows knows that this is an upgrade so it will continue.
7.  After installing and expanding files...and rebooting once or twice (depending on machine)...you will be promted to set Windows up...asking you for the DVD Key...put it in and continue until finished.

You're done...now if you chose to activate upon going into Windows immediately...you should be activated.  I chose to activate once I wanted to ...chose to test a few apps first...once satisfied...I activated...

The upgrade installer WILL NOT continue to install if you do not have an OS on your drive.  The only other way to do the install clean, THIS WAY, is to use the old Vista trick.  Install Win 7 and do not insert a DVD Key.  See...when you are even doing the custom install over an OS...you are not asked for a DVD key until the end, where on a clean install you are asked for the key at the start.  When prompted (with no OS)...don't put any key in and do the install.  Once in Windows...you have to run the upgrade program again, this time using the DVD key.  I, personally, choose method 1 of the custom over old OS...choosing to format the drive which then gives you a clean install

Experimentation is a good thing!

Good Luck

Bob

What if you upgrade the hard drive, how does that work? The reason I ask is I have windows 7 and plan on upgrading the drive on this computer and moving this raid array to a different system. Can I simply remove the old drives, slap in the new one, and re-install? Or will I have to install XP on there and upgrade from there? Thanks all for your help.

Just to make sure that I got the clean install...I installed XP on my RAID array...then did the Win7 install and chose custom and formatted.  Installing XP took all of 15 minutes on my E758 board and Two VelociRaptors.  Worth the effort...

If you do NOT install another OS...you still have to do the latter trick of installing without using the Key code...then once in Win7...run the upgrade from within...and use the DVD Key the second time.  Most times...all Win7 will do is look for missing files and install them..

Bob

Thanks for the link.

BOBMITCH,

i have a question or anyone that knows the answer i just started a fresh install and followed bob's directions and chose FORMAT and hit the OK button. did it format that quick? i just hit the button and that was it i never saw it do anything so i just chose NEXT and it started the install process? did i do something wrong or miss something?

lascivious1


BOBMITCH,

i have a question or anyone that knows the answer i just started a fresh install and followed bob's directions and chose FORMAT and hit the OK button. did it format that quick? i just hit the button and that was it i never saw it do anything so i just chose NEXT and it started the install process? did i do something wrong or miss something?

all a quick format does is remove the first charecter of the files so they are not seen, and reset your alocation table, all the information is there but now windows knows to write over it when it needs to. That's why it's so fast, If you need to be sure it's gone there is a DOD wipe program that writes 1's and 0's over the information 7 times ( that way you know it's gone.) but that takes considerablly longer.

Yes this definitely deserves to be a sticky!
 Ed Bott does good job of covering most if not all the scenarios that can occur and answers like 99% of questions about this we get on the boards so I suggest everyone read it when they get a chance.

If you just want your upgrade CD to work and you are having any problems just use this guide from Paul Thurrott.
http://www.winsupersite.com/win7/clean_install_upgrade_media.asp

Was just talking to a friend of mine who did this recently and
I wanted to see if I could reformat then just use my DVD upgrade
to install w/o an OS installed.

Now I know I can't... really...
Glad I found this thread, thanks again.

If you are at that point in the installation where it is time to enter the product key and you know you are entering the right key code but it won't take it returning an error that reads something like "not a valid key code" then M$ is searching for a previous installation and will not validate until it finds it. You are likely in the same situation I recently found my self in.

So, just a note here in hopes it will help someone out. First off I have Window 7 upgrade media on this machine and I recently lost a single hard drive of a raid array. Needles to say a format and reload was required once the new drive was replaced and raid rebuilt. Originally I had upgraded an XP machine but this install there would be no XP to upgrade. No problem right?..... You could install XP first however don't be afraid mother M$ will be there for you albeit a pain in the rear.

Proceed with installation as recommended by M$ and chose Custom when prompted.

At the point where you enter the product key don't bother it won't accept the key just click next with out entering the key and let the installation complete. Once at the desktop you will want to activate Windows but first you will have to call home. Remember in order to get all windows updates it will require an activated windows OS. When you make the call you will be asked a couple questions like is this copy installed on another machine and what happened to get you there but I did not have to prove I had XP or anything like that. The process is really quit simple and straight forward. The tech will have you initiate a program already on your machine "MSDT" and give you a 10 digit key code, at the appropriate time, that will allow your copy of Windows to be validated. With a quick restart you will verify Windows has be activated and the whole process will take you aprox. 10 minutes.

While on the phone the tech verified for me that any type of upgrade is supported CPU motherboard etc no problem. Furthermore he recommended that I keep the Case number to expedite matter in the future if need happens arises again. It's a simple process to reactivate the ticket and helps expedite the next go round.

Inconvenience aside it was painless really. The call was answered almost immediately too. The tech spoke English exceptionally well, was very friendly and very helpful. I must admit M$ has improved the experience and I didn't have to go through the hoops mentioned in the links above, ie: double install.
Quit frankly there is no need to "cheat", so to speak the system when there 's a much easier way.

I hope all you experiences with windows goes as smoothly for you as this did for me. Good Luck!

I've done the 'install over' trick for other reasons.  Fatal System Error caused by failed updates, installed over, not a problem till the board went out.

I'm on my second keycode, but that's not a problem at all yet.

This Procedure is not recommended by MS, it does work I have used it twice.

1. Perform a custom clean install using upgrade media.
2. Make sure to deselct  Automatically activate Windows when I'm online
3. Open regedit.exe with and navigate to: HKEY_LOCAL_MACHINE/Software/Microsoft/Windows/CurrentVersion/Setup/OOBE/
4. Change MediaBootInstall from "1" to "0".
5. Open the Command Line Utility "Run as administrator".
6. In the Command Line Utility window, type: slmgr /rearm.
7. Close the Command Line Utility and reboot.
8. When Windows 7 reboots, run the Activate Windows utility, type in your product key and activate windows.

 If the procedure fails you will have to perform the "double installation".

Nice JDAM! thanks for finding this and adding to it that's some good stuff there! I think you deserve a Blue Ribbon for that let me see what I can do.

They need to make it so that if you have an upgrade version, you can enter that key when installing it, then have it ask for the previous version's key.
 
IE I have windows 7, if I install from the windows 7  CD I should be able to enter the upgrade key, then have it ask for the vista key. that way it knows that you have both the base and the upgrade (and not just the upgrade) and you don't have to double install.
 
That's the way it should be imo, no need for any tricks.
 
Edit: and no, it's not thread necromancy, this is a sticky so it's alive, even if cryogenically frozen.