I advise installation of a SSD Crucial/Samsung or Intel. The Crucial 256 GB MX100 or 550 are a good buy: [URL] Regarding Windows installation follow my instructions here to download Windows 8.1 installation media: [URL] For full installation instructions see A Clean Install of Windows 8.1: [URL] If you need additional help with driver installation, provide the hardware IDs after installation of Windows 8.1: [URL]
Im using dell inspiron 3521 windows 8 preloaded.  Last week my hard drive crashed. And i dont have any recovery backup disk or usb. And now im going to buy a new internal hard drive. But dont know what to do after buying the hard drive. I know how to fit the hard drive. But dont know the step to do after that. And one more thing. Is it important to buy the same hard drive or i can buy a different one. Pls suggest me some good brands.. And steps to do after fitting the hard drive. 
How to install windows on empty hard drive.