Microsoft released the final version of its proprietary antispyware application, Windows Defender. The security tool, which saw its last public beta release in February, is a free download for US customers running Windows and promises to protect PC owners from malicious spyware hacks entering their systems.

Beta versions recorded a total of 34 million downloads, according to a Microsoft spokesperson. This would indicate some modicum of popularity for the Microsoft program, which is now competing with other free software offered by PC security providers like Spybot and Lavasoft.

This isn’t the only competition that has begun to spring up between Microsoft and other security providers. There is looming controversy over Windows Vista and the access that’s been provided to companies like Symantec and McAfee, two of the most prolific PC security providers. They claim Microsoft has not allowed them to explore a "kernel-level security feature" in Vista called PatchGuard.

"For an innovative security risk management vendor like McAfee, that offers its customers comprehensive security protection, full and unfettered access to the kernel is vital if we are to protect users," McAfee said.

Microsoft security expert Sandi Hardmeier is less than sympathetic, however. "If McAfee and Symantec did a little more coding and a little less complaining, they might get somewhere," she said in one of her blog entries.

Microsoft is planning to offer its own comprehensive security solution for the upcoming Vista platform, which is due to launch in the early part of next year.