professional product key to activate windows 7 professional

You can only obtain a product key by purchasing the product -- and legitimate copies of Windows 7 Professional are getting very difficult to find (and correspondingly expensive).

Do not buy a product key on its own.

If you are reinstalling Windows 7, use the product key on the COA sticker on the computer (for machines that came with Windows pre-installed).  The edition of Windows you're installing must be exactly the same as the edition originally installed at the factory.

Microsoft no longer sells Windows 7.

Warning:

You do not buy a Product Key by itself, as they are normally stolen/pirated, Volume Licenses which are not for private use, or MSDN keys which are not to be sold by the original subscription holder.

Make sure that you buy the complete sealed package (DVD, license)

https://www.microsoft.com/en-us/howtotell/Shop.aspx

Read Section: Beware of Product Keys sold separately.

@@@@@@@@@@@@@@@@@@@@@@@@@@@@

If you had already paid for 7 Pro yourself or it came preinstalled:

Is it a Retail, OEM System Builders or OEM preinstalled (Dell, HP, etc.) license and is it still activated?

@@@@@@@@@@@@@@@@@@@@@

The Product Key consists of 25 digits, divided into 5 groups of 5 digits and the layout looks like this:

xxxxx-xxxxx-xxxxx-xxxxx-xxxxx

The 24 used are:

2346789BCDFGHJKMPQRTVWXY

The 12 unused are:

015AEILNOSUZ

@@@@@@@@@@@@@@@@@@@@@

If installed and activated and a Retail or OEM system Builders license and you have lost the product key that came with the purchase use these free programs:

http://www.belarc.com/free\_download.html

https://www.magicaljellybean.com/keyfinder/

@@@@@@@@@@@@@@@@@@@@@

If you bought it from Microsoft:

Find your downloads and product keys

Most software you buy directly from Microsoft Store as a digital download, like Office, Windows, and Xbox games, can be downloaded, installed, or reinstalled inorder history. Find the software and then selectProduct key/Install.

@@@@@@@@@@@@@@@@@@@@@

If OEM preinstalled (Dell, HP, etc.) license:

The COA sticker, which has the Product Key on it, is either on the underside of the Laptop or in the Battery Compartment.

With a Desktop it is either on the side, rear or top of the Computer Case.

Product Key finder programs do NOT find a useable product key on OEM preinstalled operating systems (Dell, HP, etc.)

Key Finder Programs used on preinstalled Operating Systems only find the Manufacturer's Product Key which was used on multiple machines during manufacture and what they find is not suitable to use for a reinstall or activation problems.

Cheers.