April 12th is the very last day. That's when the clock runs, and the deadline looms.
And here you thought it was April 15th. Nope, it's the twelfth. Because we're not talking about the day your taxes are due. On no. We're talking about the day that your Windows XP or Windows XP SP1 computer will be automatically updated to XP SP2 (Service Pack 2) whether you want it to or not. Period.
Up until now users who did not want to accept the SP2 update had the option of temporarily blocking the update from being downloaded to their machines through the Automatic or Windows Update mechanisms, however that option expires on April 12th.
According to Microsoft's latest alert on the issue, "The intent of this alert is to provide you with a reminder about the upcoming deadline around the date on which Automatic Update (AU) and Windows Update (WU) will deliver Windows XP SP2 regardless of the presence of the blocking mechanism."