Is your business ready for the move to Windows 8? You might want to start moving users to Windows 8 to get the better security, or the option of running Windows from a USB stick with Windows To Go; they might ask for Windows 8 to get the extra battery life on a notebook. Even if you're not planning on switching immediately, given the popularity of Microsoft's Surface tablet, you can expect users to start bringing Windows RT devices to work soon and the PCs you buy will soon start coming with Windows 8.
You don't need a new PC for Windows 8. Almost any PC that runs Windows 7 – or even Windows XP – can run Windows 8; as long as you have 1GB of RAM (2GB for a 64-bit system), 16-20GB of free disk space and a DirectX 9 GPU with a WDDM 1.0 driver or better. What you need to bear in mind is the screen resolution and whether the CPU supports Physical Address Extension (PAE) and the NX (No eXecute) bit.
PAE is required for NX to work correctly, and NX is what Windows uses to mark sections of memory that are only used to store data. That tells Windows not to run any instructions from those areas of memory, which stops the most common type of security exploit – filling an area of memory with instructions that are too big to fit and 'overflow' in such a way that they get run as code.
Insisting that you have to have a PAE-NX-capable CPU means you can't install on systems with some CPUs that actually meet the 1GHz minimum speed to run Windows 8 – like the Pentium M with 400MHz Front Side Bus – but it also improves security for Windows 8.
If you want to use Hyper-V in Windows 8, you need a 64-bit CPU with second-level address translation (SLAT) and another 2GB of RAM to run the hypervisor. Most PCs manufactured before Windows Vista aren't able to boot from a USB; and that won't stop you running Windows 8, but it does mean you have to install from DVD rather than a USB drive.
The screen resolution won't stop you installing Windows 8 either (even the 800 by 600 of a netbook), but it might stop you using some of the features. You can't run any WinRT apps – including the Windows Store you need to get WinRT apps – unless the resolution is at least 1024 by 768. And if you want to snap two WinRT apps side by side on screen, you need a screen that has at least 1366 by 768 resolution.
You don't have to have a touch screen, although Windows 8 is certainly easier to use if you do. Only newer touch pads support the touch gestures for opening the charm bar, bringing up the app bar and switching applications; you need the right drivers as well. The latest drivers for the Microsoft Touch Mouse give it the Windows 8 gestures, which is probably the easiest way to add touch functionality to existing desktop PCs.
While most keyboards have the Windows key, you'll need to have a Windows 8 compatible keyboard to get the most out of the new OS, particularly if you're not going to splash out on a touch screen. Keyboards designed for Windows 8 come with keys for the different charm bar icons like Settings and Devices; new Microsoft keyboards like the Sculpt Comfort also have buttons for opening the app switching pane, snapping apps side by side and swapping them around on screen. Again, this makes actually using many of the new Windows 8 features rather easier.
There's one feature in Windows 8 you do need a new PC for; Connected Standby only works on Windows RT devices or on PCs and tablets powered by a System on Chip processor like the Intel Atom Z2760 or forthcoming AMD APUs.