If you’re looking to download the latest test build release candidate of Microsoft’s new Windows 7 operating system, you’ll have until this Thursday to download your free copy.

Microsoft has allowed unlimited downloads of Windows 7, but is set to entirely close downloads as we inch closer to the Windows 7 October launch.

Users will still be able to obtain registration keys and register Windows 7, but will not be able to download fresh copies.

The Windows 7 test build will entirely expire on June 1, 2010, so you’ll have to be sure to back up your data prior to that date. Post March 1, 2010, the OS will only operate for two hours straight until a restart is required.

The version currently available for download is the final test build that will be released before the actual final version is sold worldwide in October.

If you already have a previous build installed, you’ll have to do a clean install to get the upgrade working, so you’ll have to backup your data again.

If you are looking to install Windows 7 on your Mac OS X based machine, ensure to check out our how-to guide on installing Windows 7 on Mac.

Windows 7 Home Premium will cost about $120 for the upgrade version, or about $200 for the full version. Interestingly, the same version is expected to cost a lot less in the UK, at only $106 for the full version. The UK prices are already listed on Amazon.