Download windows 7 and install using the genuine product key.

As long as you have the product key on the COA sticker follow the instructions listed below.

1) Download the appropriate Windows 7 .ISO file which includes Service Pack 1
(Note: must match what your product key version is for)

How to find out if I have a 32 or 64Bit version of Windows installed on my computer:
http://windows.microsoft.com/en-us/windows7/find-out-32-or-64-bit

Windows 7 Home Premium 64Bit:  http://msft.digitalrivercontent.net/win/X17-58997.iso
    SHA1 Hash value: 6c9058389c1e2e5122b7c933275f963edf1c07b9

2) After downloading the correct .iso file install HashCalc and validate the SHA1 hash value
is correct.
HashCalc: http://www.slavasoft.com/hashcalc/index.htm
(note: If the download is not corrupt, the value HashCalc returns will match the SHA1 value I posted)

a) Launch HashCalc and navigate to the location of the .iso file you downloaded.
(The default download location is: C:\Users\User account name\Downloads)
b) Remove all check marks from the list of HashCalc options except for SHA1.
c) Click the ‘Calculate’ button and wait for the SHA1 string of letters and number to be displayed.

3) Next use ImgBurn (or Gear ISO) to create a bootable DVD.
Choose the “Custom Installation (advanced)” option and remove the check mark(s)
to eliminate unwanted options.

ImgBurn - In addition to supporting the creation of Cds/DVDs from .ISO files,
it supports a wide range of other image file formats, and it's free.
(BIN, CUE, DI, DVD, GI, IMG, MDS, NRG, PDI and ISO)
http://www.imgburn.com/

Screen shots to help you use ImgBurn: http://www.imgburn.com/index.php?act=screenshots
Burning ISO Images with ImgBurn article: http://neosmart.net/wiki/display/G/Burning+ISO+Images+with+ImgBurn
(The steps are the same for Windows 7 or Windows 8), except you are not creating a Repair disc but a full installation DVD)

Note: Always use high quality DVD+R media and the slowest burn speed (4x or 6x) if offered a choice.

4) For instructions on creating a bootable USB Flash drive to install Windows 7:
Read: http://www.sevenforums.com/tutorials/2432-usb-windows-7-installation-key-drive-create.html
Or: http://arstechnica.com/business/2009/12/the-usb-flash-drive/

Optional software to create a Bootable Windows 7 DVD
http://support.microsoft.com/default.aspx/kb/977640

====================== Keyless Install ================================

How to perform a 'Keyless Install' of Windows:

Boot from the Windows 7 DVD disc you created and start the installation process.

After you enter user name and password you will be asked to:
'Type your Windows product key',  do not enter a key.
Also located just below the box where you would enter the key is a box with a check mark
to 'Automatically activate Windows when I am online', remove the check mark and click 'Next'.

You will now have a 30 day grace period in which to activate Windows.

During the grace period you can install your device drivers,
run Windows Updates and resolve any other problems or issues.
Once you are satisfied everything is functioning properly, then activate Windows.

====================== Device Drivers ===============================

Go to your computer manufacture's support web site and check for Windows 7 drivers for your specific model number.

If there are Windows 7 drivers, then download to a folder on your hard drive and install all of them, starting with the Motherboard/chipset drivers, SATA, LAN, Audio, USB, Graphics, Webcam, Etc., and so on.

List of Computer Manufacturer's support sites:
http://windows.microsoft.com/en-US/windows/help/contact-support/computer-manufacturers

Tips for fixing common driver problems
http://windows.microsoft.com/en-US/windows7/Tips-for-fixing-common-driver-problems
Vista: http://windows.microsoft.com/en-US/windows-vista/Tips-for-fixing-common-driver-problems

Graphics/Video drivers:
Check the Graphics card manufacture's download site for the most recent Windows 7 drivers for your card.
ATI: http://support.amd.com/us/gpudownload/Pages/index.aspx
NVIDIA: http://www.nvidia.com/Download/index5.aspx?lang=en-us

================== Run Windows Update ===========================

Install the 'Important' updates that are available.

Do a small group (10 updates max at a time) of updates at a time,
reboot if prompted and install another small group of updates and so on,
saving any .NET Framework updates for last.

================== How to Activate Windows 7 by Internet ==============

1) Click Start and in the Search box type:   Activate 
2) Click on the 'Activate Windows' option at the top of the list
3) Click on 'Activate Windows online now'
4) Enter your 25 character product key (not case sensitive)
5) Click 'Next' and wait for the key to be verified.

Alternate Method - Reaching a real person:
1) Click Start, and in the Search box type:   slui.exe  4
2) Next press the 'ENTER' key
3) Select your 'Country' from the list.
4) Choose the 'Phone Activation' option.
5) Stay on the phone *** do not select/press any options *** and wait for a person to help you.
6) Explain your problem clearly to the support person.
7) The support person should give you a confirmation ID, copy it down on paper,
8) Verify the ID is correct by reading back to the support person.
9) Enter the ID number and click 'Next' to finish the activation process.

Microsoft Activation Centers Worldwide Telephone Numbers:
http://www.microsoft.com/licensing/existing-customers/activation-centers.aspx
(This site is for Volume License Activation but if you call they will help you)

The phone number you called does not work:
Microsoft Worldwide contacts: http://www.microsoft.com/worldwide/default.aspx

Activation and registration of a Microsoft product
http://support.microsoft.com/?kbid=326851
Windows activation: (888) 571-2048

======= Create an Image Backup to protect your time and investment ==============

EaseUS Todo Backup Home V7.0 http://www.todo-backup.com/
Free version: http://www.todo-backup.com/products/home/free-backup-software.htm
Version comparison chart: http://www.todo-backup.com/products/home/comparison.htm
Includes: Incremental backup, Disk/partition clone
User's Guide: http://www.todo-backup.com/download/docs/User_Guide.pdf
(Note: Install Todo and then create an "Emergency Disk" before you start creating your first image backup)
Version 7.0 supports XP, Vista, Windows 7, 8 and 8.1

Acronis True Image 2014 - has a 30 day trial version available, trial Key send via Email.
Note: Cloning and drive initialization (creating a MBR) are not supported in the trial version.
For the trial version, only recovering is available when booting from an Acronis Bootable Media.
Install Acronis and then create a bootable Restore/Rescue Media CD before you start creating your first image backup
http://www.acronis.com/homecomputing/products/
30 day trial:  http://www.acronis.com/homecomputing/products/#tryorbuy
True Image User Guides and documentation:
http://www.acronis.com/support/documentation/
2014 supports XP, Vista, Windows 7 and Windows 8 and 8.1

Note: For users who have a Western Digital disk drive there is a free version of Acronis 2013:
http://support.wdc.com/product/downloaddetail.asp?swid=119
Release notes: http://support.wdc.com/download/notes/ATI_WD_RN_5962.pdf
Users Guide for WD Version: http://support.wdc.com/product/downloaddetail.asp?swid=119&type=userguide&wdc_lang=en

Paragon
Free version: http://www.paragon-software.com/home/br-free/
User'sGuide: http://www.paragon-software.com/home/br-free/download.html
Home Version $39.95: http://www.paragon-software.com/home/brh/
Support: http://www.paragon-software.com/support/

Macrium Reflect Free
Free version: http://www.macrium.com/reflectfree.aspx
(no technical support available for the free version)
Macrum Reflect Standard ($49.99)
http://www.macrium.com/personal.aspx
Suport: http://www.macrium.com/ticket.aspx

J W Stuart: http://www.pagestart.com

If win7 was preinstalled by the laptop maker you should have made the recovery disks as per that makers instruction. Call their support to request the recovery disks

Or check this site for your other options, which have been posted many times before {Hint} the related Content links