Cole was referring to the "endless reboot" snafu that users began reporting after applying the service pack upgrade; last week Hewlett-Packard, whose AMD-powered machines were cited by most users as the only ones affected, confirmed the rebooting glitch, and Microsoft announced it would add a filter to Windows Update to prevent AMD-based PCs from obtaining XP SP3 via the update service's listings.

"People need to exercise caution before [updating to] XP SP3," said Cole. "This may well go beyond Symantec."

For its part, Microsoft has remained mum. Although a Microsoft engineer asked users on the support forum for additional information -- and provided an e-mail address for them to forward details -- the company did not address questions put to it Monday that asked it to confirm the problem, point out any posted Microsoft solutions and fix blame on either Symantec or its XP SP3 update.

Microsoft limited its response to boilerplate language that it's used before in statements about XP SP3. "Customers who experience a problem with Windows XP SP3 installation should contact Microsoft Customer Support Services, which can provide free assistance and troubleshooting for these issues," a company spokeswoman said in an e-mail Monday afternoon.

Some users, in fact, reported that they had contacted Microsoft's help desk, and via a remote session managed by the tech support representative, had had their Windows registry cleaned. Many others, however, vented at the apparent lack of interest by Microsoft in their troubles.

"I see no evidence that Microsoft is working on this issue, or even that they are mildly concerned about it," wrote "Sandbridge" Friday.

MRFREEZE61 posted clean-up instructions for afflicted users on the Microsoft support forum, and several reported back that the work-around had done the trick. "Hey Mr. Freeze, just wanted to say that your solution saved my butt big time," said someone identified as "RevDAGG" on Sunday.

Manually deleting the rogue registry keys, however, was impossible for some, who reported thousands, even tens of thousands, of corrupted entries; several called for an automated tool to help them do clean-up.

"Once we've figured out how many customers this affects, [an automated tool] is absolutely possible," said Symantec's Cole. "If there is something we can do to address the problem, we'll do it."