Microsoft Corp said on Tuesday its new Windows 7 operating system will be generally available on October 22, well ahead of its original schedule and in time for the holiday shopping season.

The new operating system, which will replace the unpopular Vista, was originally planned for roll-out at the beginning of next year, but Microsoft confirmed last month that it would hit the market in time for the year’s busiest buying period.

Chinese authorities shut down blogs, Internet forums and social media sites such as Twitter in an apparent attempt to stem online political discussion ahead of Thursday’s 20th anniversary of the bloody crackdown on 1989’s Tiananmen Square pro-democracy protests.

As in past years, dissidents were rounded up and shipped out of Beijing and foreign media reports on the protests and continuing calls for an independent investigation into the events of June 3-4, 1989, have been blocked.

However, the cut off of Internet sites marks a new chapter in the authorities’ attempts to muzzle dissent, one that testifies to the burgeoning influence of such technology among young Chinese in an authoritarian society where information is tightly controlled.