With software giant Microsoft having started accepting orders for its forthcoming Windows 8 operating system this week, the `upgrade' option for the users of the previous Windows versions is now available.

Though the scheduled release date of the Windows 8 OS is October 26, the option of upgrading to the newest OS version is now open to all PCs users who possess a system which runs the earlier versions of the Windows OS.

The Windows 8 upgrade is priced at between $14.99 and $39.99; with the lower cost being offered only to those PC owners who have purchased a Windows 7 system after June 2.

For all the other PC users who have a Windows-powered system, the option to upgrade to Windows 8 OS will be available at a higher cost.

The opportunity for the Windows PC users to avail the `Windows 8 upgrade' advantage at the mentioned prices will be possible only till January 31, after which the offer will be discontinued.

The key reasons for existing Windows users to upgrade to the Windows 8 version of Microsoft's OS could probably include the much-hyped new user interface of the forthcoming OS, as well as the fact that the software has been so designed that it boasts the capability of running both traditional PCs and tablet computers.