Windows 7 System Requirements

If your PC can run Microsoft windows vista, then your PC will be able to run Microsoft windows 7.
As per latest released of Microsoft, minimum system requirements for windows 7 are given below:-

• 1 gigahertz (GHz) or faster 32-bit (x86) or 64-bit (x64) processor
• 1 gigabyte (GB) RAM (32-bit) or 2 gigabyte (GB) RAM (64-bit)
• 16 gigabyte available hard disk space (32-bit) or 20 gigabyte (GB) (64-bit)
• DirectX 9 graphics processor device with WDDM 1.0 or higher internet access.

Note:-
* If you plan to use in Windows XP Mode, you will need at least 2 gigabyte (GB) of RAM and 15 gigabyte (GB) of extra storage space along with a processor that supports hardware virtualization.

* Windows 7 minimum system requirements are generally applied to all editions of Windows 7 operating system.

Hardware requirements for Windows 8
Additional requirement:-

• Internet access.
• For some Windows Media Center functionality a TV tuner and extra hardware may be necessary.
• Windows Touch and Tablet computers need specific hardware.
• Home Group requires a network and computer running Windows 7.
• DVD/CD authoring requires a compatible optical drive.
• Depending on resolution, video playback may require additional memory and advanced graphics hardware.
• Some games and programs might require a graphics card compatible with DirectX 10 or higher for optimal performance.
• Windows XP Mode requires an extra 1 gigabyte of RAM and 15 gigabyte of available hard disk space. 
• Music and sound require audio output.