Upgrading from Windows 7 to windows 8

That is not an "upgrade", but rather a downgrade going from Windows 7 to 8 (at least in my point of view)....

What type of license did you buy for windows 8? As long as it isn't an "upgrade" license, I suggest you use a different way of installation.

1st. way:

Get another HD and remove your current one from the PC, then install Windows 8 to the new one. That way you can put the old disk back in and use your old OS if needed.

2nd way:

Shrink your partition on your current HD using diskmanagement. Then install Windows 8 to the empty space you created. A new boot menu will appear where you can select to which OS you want to boot to.

3rd way:

Install VMware Player inside your current Windows 7 PC. Then install Windows 8 as a Virtual Machine (VM). Now you can start Windows 8 from within Windows 7. Just make sure you have enough RAM in your PC to run both OS's at the same time.

Most PC come pre-installed with an OS from the factory, and those OS's are usually OEM. Also, most such PC's have a recovery partition so you can quickly restore the system to factory defaults. To return such a PC back to factory defaults you normally never have to enter the key for the OS, it is already there. Check the manual for your PC, or online at the manufacturer's site for details how that is done. Apart from that, as most of these PC's aren't delivered with installation media, there is also a utility included that allows you to make one set of recovery DVD for the case that the hard-disk should break down. That should always be done right after having unpacked and run your PC the first time. The problem is that most people ignore this, or don't know about it, or forget to make those media. If you haven't, then again check your manual for details on how those media are created. Do that before starting the installation of Windows 8.

above three methods are only applicable if you have bought new windows 8 license , not an upgrade license ,

I am clarifying of the upgrade license , under this this would only be upgrade media , not the whole windows 8 media , and it should only accept the upgrade keys as explained by  yagyashree

What do you say , A link from microsoft may help answer this question which is already quite clarified by: yagyashree .

so , if I dont want to use windows 8 , and want to revert back to windows 7 , would i have to run recovery and get bcak to windows 7 with win 8 license as you saying windows 7 is no more valid and only win 8 license would be valid as of backward compatibility ???

I know once we have to upgrade windows 2003 server to win 2008 serv , we were given keys which were then even valid for win 2003 as well for the backward compatibility .

please suggest ?

Did you manage to get an answer for your query?

Since , I am too busy in other stuff , dont have time to see my own laptop . but thanks for your all comments and support .