Did you create the Windows 7 - IMPORTANT Windows 7 Backup Disks to create
Restoring Your Dell Computer to Original Factory Installation with Dell DataSafe Local Backup 2.0
Restoring Your Computer´s Software to the Factory Settings
How To Restore or Reinstall Microsoft® Windows® on a Dell™ Computer
What is a Dell Service Tag and how do I locate it?
Original poster, If you have solved your problem, can you please mark the correct thread(s) with your solution. Thanks
Welcome to Dell Community!
See my clean install of Windows 7 guide below; it will tell you every step in performing a clean install and where to download all you need.
Performing a clean install will give you optimal performance.