Computers running chips made by Advanced Micro Devices could seize up and display the so-called Blue Screen of Death if upgraded to the latest service pack for Windows XP, Hewlett-Packard warns.

"During Windows startup, computers with AMD processors may experience a blue screen error" if they're upgraded from Windows XP SP2 to Windows XP SP3, HP said in a service bulletin posted on its Web site.

HP said the problem could occur because XP SP3 tries to place on computers a power management driver that's only supposed to run on PCs that use Intel chips. The driver can cause AMD-based computers to crash or enter a cycle of reboots, HP said.

Both HP and Microsoft are working on a patch for the problem. Until then, experienced PC users can work around the bug by starting AMD-based machines in Safe Mode and disabling the Intel power management driver.

Other problems have been reported as well.

Within hours of its general release earlier this month, Windows XP SP3 began drawing hundreds of complaints from users who claim the update is wreaking havoc on their PCs.

The problems with XP SP3, according to posters on Microsoft's Windows XP message board, range from spontaneous reboots to outright system crashes.

"My external disks are having trouble starting up, which results in Windows not starting up," complained user Michael Faklis, in a post. "After three attempts [to install XP SP3] with different configurations each time, System Restore was the only way to get me out of deep s**t," said "Doug W."

Another user said the service pack prevented him from starting his computer. "I downloaded and installed Windows XP Service Pack 3 Network Installation Package for IT Professionals," wrote "Paul." "Now I can't get the computer to boot."

Dozens of other posters reported similar problems.

It's not uncommon for major operating system updates to cause problems. Typically, the glitches are caused by conflicts with software, such as drivers, system files, or applications, already resident on the user's PC. Microsoft has yet to indicate whether it will issue an update to address some of the more common problems, though it has done so with previous updates.

Microsoft released Windows XP SP3 to broad distribution in early May. It's available from Microsoft's automated Windows Update service or as a file that can be pulled from the Download Center on the company's Web site.

The service pack should offer a number of enhancements over the current version of the OS. It includes all updates issued since Windows XP Service Pack 2 was released in 2004, and some new elements.