Feb 12, 10:23 PM (ET) By ALLISON LINN SEATTLE (AP) - Microsoft Corp. (MSFT) said late Thursday that portions of its Windows source code - the tightly guarded blueprints of its dominant operating system - had been leaked over the Internet. Microsoft spokesman Tom Pilla said in an interview with The Associated Press that some incomplete portions of the Windows 2000 and Windows NT4 source code had been "illegally made available on the Internet." Access to the source code could allow hackers to exploit the operating system and attack machines running Windows, which is used on hundreds of millions of...