To run Windows 8 on your PC or laptop you will need to make sure that the system meets the minimum specifications. For a basic Windows 8 setup, these are quite low and any Vista capable machine should also be able to cope with a basic Windows 8 install.
The base specs are as follows:
Processor: 1 gigahertz (GHz) or faster with support for PAE, NX, and SSE2 (more info)
RAM: 1 gigabyte (GB) (32-bit) or 2 GB (64-bit)
Hard disk space: 16 GB (32-bit) or 20 GB (64-bit)
Graphics card: Microsoft DirectX 9 graphics device with WDDM driver
However to use certain features there are some additional requirements too:
Internet access (ISP fees might apply)
To use touch, you need a tablet or a monitor that supports multitouch (more info)
To access the Windows Store and to download and run apps, you need an active Internet connection and a screen resolution of at least 1024 x 768
To snap apps, you need a screen resolution of at least 1366 x 768
Secure boot requires firmware that supports UEFI v2.3.1 Errata B and has the Microsoft Windows Certification Authority in the UEFI signature database
Some games and programs might require a graphics card compatible with DirectX 10 or higher for optimal performance
Watching DVDs requires separate playback software (more info)
Windows Media Center license sold separately (more info)
BitLocker To Go requires a USB flash drive (Windows 8 Pro only)
BitLocker requires either Trusted Platform Module (TPM) 1.2 or a USB flash drive (Windows 8 Pro only)
Client Hyper-V requires a 64-bit system with second level address translation (SLAT) capabilities and additional 2 GB of RAM (Windows 8 Pro only)
A TV tuner is required to play and record live TV in Windows Media Center (Windows 8 Pro Pack and Windows 8 Media Center Pack only)
Free Internet TV content varies by geography, some content might require additional fees (Windows 8 Pro Pack and Windows 8 Media Center Pack only)
Microsoft has created a very useful tool that can be used to find out if your machine is capable of running Windows 8 called the Upgrade Assistant and it is recommended that you you run it, even if you think that your machine is capable of running Windows 8. You can also find further, more detailed information on the help page How To Get Windows 8.
If you are going to develop for Windows Phone, you should also note that a few extra things are required of your system.
The most important of these is to ensure that your hardware and software meet the minimum requirements set by Microsoft for the SDK and the VM Phone Emulator to be used. This means that you must have the following: