If you already own a PC with a 64-bit processor why not take a look at this preview of the 64-bit version of Windows XP Professional?
The OS promises many benefits over the current 32-bit edition, including support for up to 32Gb of Ram and 16Tb of virtual memory.
The software is time-limited and will expire in 360 days. You will need to register with Microsoft in order to download the software, as the download link and a product key is sent to you via email.
Also bear in mind that the OS is not compatible with 64-bit Intel Itanium-based systems.
