Hi Ajay Chandran, Welcome to Dell Community Forum. As I understand, your Dell Inspiron 15R 5521 came pre-loaded with Windows 8 and you wish to downgrade to Windows 7. Please click on the link below for an article on how to downgrade from Windows 8 Pro to Windows 7 Professional. [URL] This article discusses the critical steps that you should take before and after downgrading to Windows 7 Professional on a factory-installed Windows 8 Pro computer, such as creating recovery media for Windows 8 Pro, downloading appropriate drivers in advance, and changing system properties. The instructions provided in this document are specifically provided for customers who have purchased computers pre-installed with Windows 8 Pro who wish to downgrade their operating system to Windows 7 Professional. Microsoft does not provide a downgrade path for customers with other versions of Windows 8, and Dell may not provide legacy driver support for Windows 7 Professional on computers factory-shipped with Windows 8 Pro. To enable downgrade to Windows 7 on this system the BIOS settings on this system were changed to boot into legacy BIOS mode. If the BIOS setting is not changed to native UEFI mode boot prior to installing, Windows 8 Pro will install; however, the following Windows 8 Pro functionalities will not work as they rely on a native UEFI mode boot. •Secure Boot•Seamless Boot experience•Network unlock for Bitlocker for systems with a Trusted Platform Module (TPM).•eDrive support Please go through the complete article prior to attempting Windows 7 installation. Additionally, you may also check this link for useful information: [URL] Hopefully, you will find the information provided in the links helpful in resolving your issue. Please back up all relevant data on your computer prior to attempting re-installation as this may result in data loss. Let me know if further help is needed. Thanks and regards,Babita S#iworkforDell  For easy access to drivers, manuals and product updates, please visit our Support Site .
i've bought inspiron 15r-5521 with intel corei5 and amd radeon hd 8730m.....i've got problrms with using windows 8...i've tried to install windows 7 but i cant...the dvd dosent boot and the bios has no alternate boot options..plz help me to install windows 7..
problem with inspiron 15r-5521- installing windows7