Microsoft issues its biggest-ever security fix

The new patches aim to fix a number of vulnerabilities including the notorious Stuxnet virus that attacked an Iranian nuclear power plant and other industrial control systems around the world.

Microsoft said four of the new patches -- software updates that write over glitches -- were of the highest priority and should be deployed immediately to protect users from potential criminal attacks on the Windows operating systems.

Microsoft said it also repaired other less serious security weaknesses in Windows, along with security problems in its widely used Office software for PCs and Microsoft Server software for business computers.

Microsoft released 16 security patches to address 49 problems in its products, many of which were discovered by outside researchers who seek out such vulnerabilities to win cash bounties as well as notoriety for their technical prowess.