Computerworld reports that Microsoft has been having major problems with its WGA servers since at least Friday evening. "An unknown problem in a controversial Microsoft Corp. anti-counterfeit process has been fingering genuine versions of Windows Vista and Windows XP as fakes since Friday night, disabling features on potentially millions of machines. Beginning Friday around 8 p.m. Eastern, users started posting messages on Microsoft's support forums, including Vista Validation Issues, saying that their PCs had been tagged as running non-genuine Windows. Overnight, the number of users adding their accounts to the tale spiked significantly, and the frustration index jumped dramatically."  Microsoft has identified and fixed the problem and posted instructions for anyone whose system mistakenly failed a WGA check.

Isn't it interesting that the US government doesn't consider systems like WGA a threat to national security? :-)