Move up to Windows 8.

Check to see if your PC is compatible with Windows 8.

Follow the Instructions for Upgrading Your PC to Windows 8.

Windows 8 Easy Transfer
Windows 8 Installation Instructions
Upgrading from Windows 7 to Windows 8
Upgrading from Windows Vista to Windows 8

After You've Completed Your Upgrade, You'll Need to Update Your Drivers.

Additional Resources.

Upgrade to Windows 8
Windows homepage
Windows 8 Compatibility Centre