San Francisco - Chinese hackers have cracked the activation codes for Windows 7, less than a month after Microsoft released the first copies of the new operating system to computer makers, technology news site CNET reported Thursday.

The crack will allow fully functional, copied versions of the Ultimate Version of Windows 7 to be distributed over file-sharing sites even before the operating system is released to the public in October.

The pirated version even tricks the computer and Microsoft's servers into believing it is a genuine copy, allowing it to avoid Microsoft's validation safeguards.

The report said that the copied software was hacked via a disc stolen from Chinese computer maker Lenovo, but that the pirated version would work just as well on Dell and HP computers too.

Microsoft acknowledged the report of the Windows 7 breach and strongly advised users to avoid downloading the software from unauthorized sources.

"Downloading Windows 7 from peer-to-peer websites exposes users to increased risks - such as viruses, Trojans, and other malware and malicious code - that usually accompany counterfeit software," the company said in a statement.

"These risks can seriously harm or permanently destroy data and often expose users to identity theft and other criminal schemes."(dpa)