Windows 7: Reinstalling: why not simply run setup from CD

Hi everyone. Now I have to reinstall Win 7 on a machine and I wonder: we are commonly recommended after putting in the CD to restart and boot from it. But why? Why the hassle when after insertion autorun prompts me to run setup.exe so why not use it, so much simpler? Doesn’t it work the same way after that?

Plus through setup it allows you to update in advance as far as I see instead of having your machine stuck for ages at shutdown and startup afterwards.

You boot from the Win 7 installation DVD to do a clean install. You clean all the HDD (or SSD).
Is the best option to get rid of trash you collected over the years (on users profile and register)
You will have to reinstall all updates and software.
Clean Install Windows 7

When you run setup from a running Windows, you do a Repair Install. It will reinstall Windows and keep all programs and data. It will keep all the trash you collected over the years (on users profile and register).
You will have to reinstall all updates.
Repair Install

For the (offline) updates MS releases SP2 for Windows 7

Are u sure? Setup offers two modes: Upgrade (which is indeed a repair keeping programs and settings) and Custom which erases them as a clean install is supposed to do (reference: How To Reinstall Windows 7 Without Changing Your Personal Settings, Installed Programs & Drivers,Key Step: Select Upgrade Installation Type)

I think if you select the custom it'll tell you that you need to boot into the dvd. Windows can't wipe itself off and reformat the hard drive while it is running. All of us here have reinstalled windows so many times that we know the entire process.

Hi ihatecaptcha,

We are 100% sure!

Not necessarily. It is possible to clean install by running setup from the dvd. But it has to be to a different partition from your current windows installation. It will be an additional installation and will have a different OS letter.

Indeed, exactly. I figured this by myself today.. :)