Microsoft announced on Wednesday a $119.99 price for the Windows 8.1 OS for people who are still running older versions of Windows. It applies to computers using Windows XP, Windows Vista and Windows 7.

The Windows 8.1 Pro version is priced higher at $199.99.

The price tags are for a download of the OS from Windows.com or a retail-packaged DVD product sold at stores. It is the same prices that Microsoft charges users of older versions of Windows to get Windows 8 and Windows 8 Pro upgrades.

The full version of the new OS does not require users to run previous versions of Windows to buy it at the announced prices, in contrast to past practice by Windows to offer an upgrade version or a full version for those running previous versions of the OS.

The change is in response to feedback from customers, particularly those who want to build PCs from scratch, run the new OS in virtual-machine environments or on a second hard drive partition on the hardware of their choice.

People who have installed the consumer preview version of Windows 8.1 must reinstall their apps, Metro-style and desktop, when they shift from the preview to the RTM bits on Intel an ARM hardware, advised Microsoft officials. Those who didn't install the preview do not need to reinstall apps.

Those running Windows 7 who want to shift to Windows 8.1 must also reinstall their desktop apps too, including Microsoft office.

However, Microsoft advises users of computers that run on XP and Vista that while these older versions could support Windows 8.1, they are not recommending an upgrade to the new OS since the older hardware and new OS won't create an optimal experience.

Those who would insist on upgrading are advised to purchase the retail DVD instead of downloading the bits and to boot from the DVD to ensure a clean install of Windows 8.1.

Otherwise, their files, settings and programs would not transfer and users would need to back these up and reinstall them.

But consumers who purchase new devices running Windows 8.1 could buy the Pro Pack in the later part of 2013 for only $99.99. Those using 8.1 Pro could by the Windows Media Center as add-on for $9.99.

Also beginning Sept 18, the RTM bits of Windows 8.1 Enterprise to volume licensees with TechNet and MSDN subscription are available from Microsoft.