The product key was on the COA Sticker.
There are no keys to send you.
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.

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You don't say if you only "formatted" the system partition.
There should have been a recovery partition to reinstall from>
If you do not have this you will have to buy the Windows 7 package/license again, if you can not work out what the product key is.
If it came preinstalled and the product key is erased/worn on the COA sticker:
You could use a torch and magnifying glass to attempt to read it.
Or take a photo of it and enlarge it on the screen.
You can contact your Laptop Manufacturer and ask them to send you a set of Recovery Disks.
They should do that for a small cost, IF they still have them available (Most don't).
And if you never received a Recovery Disk when you received your Laptop there should be a Recovery Partition on the Hard Drive to reinstall Windows back to how it was when new.
Here are the Key/s to press at Boot to start the Recovery Process back to Factory Settings (new condition). Under each Manufacturer in the list below are the instructions in the respective links for you to follow on how to use their Recovery Partition
Acer – Press Left Alt + F10 Keys.
http://acer.custhelp.com/app/answers/detail/a\_id/2631
Advent – Tap F10 until Starting System Recovery appears
https://answers.yahoo.com/question/index?qid=20081221054701AAJT8YV
Asus – Press F9
http://support.asus.com/Troubleshooting/detail.aspx?SLanguage=en&m=X53E&os=&no=1775
Dell – Press F8 which will bring up Advanced Boot Options http://www.dell.com/support/troubleshooting/us/en/19/KCS/KcsArticles/ArticleView?docid=DSN\_362066
eMachines: Press Left Alt Key + F10
http://techchannel.radioshack.com/emachines-system-recovery-1747.html
Fujitsu – Press F8
https://forum.ts.fujitsu.com/forum/viewtopic.php?f=64&t=39428
Gateway: Press Alt + F10 Keys - As Acer owns them: press Left Alt + F10 Keys as per Acer eRecovery
http://www.ehow.com/how\_6960920\_restore-computer-using-recovery-partitiion.html
HP – Press F11 repeatedly
HP PCs - Performing an HP System Recovery (Windows 7) | HP ...
Lenovo – Press F11
http://support.lenovo.com/en\_US/detail.page?LegacyDocID=MIGR-4M7HWZ
LG – Press F11
https://answers.yahoo.com/question/index?qid=20090304161820AAiyvMn
Packard Bell: Press and hold the ALT key while pressing repeatedly the F10 key. Release the keys when a message displays that Windows is loading files.
Samsung – Press F4
http://www.samsung.com/us/support/howtoguide/N0000137/6375/93514
Sony Vaio – Tap F10 until the Edit Boot Options screen is displayed
Toshiba – Press 0 (zero)
How To: Perform system recovery - Windows 7
The above reinstallation methods do not normally require you to supply a Product Key during the Installation Process as the Manufacturers Recovery Process uses the Factory Installation Product Key to automatically Activate during the reinstallation process.
Cheers.