Microsoft has responded to numerous complaints about its new service pack for Windows Vista with an offer of free support for anyone having trouble installing or running the update.

According to Microsoft's support Web site, the company is offering no-charge Vista SP1 help for all users via e-mail and online chat. The wait time for an online chat session as of mid-afternoon Monday was about 20 minutes, according to the site.

Microsoft is also offering free Vista SP1 support via telephone for customers of its Software Assurance, TechNet, MSDN, and partner programs.

Microsoft ordinarily directs Windows users with support issues to the PC makers from whom they purchased their systems. It typically provides direct support only if the user bought a boxed, standalone copy of the operating system.

But Microsoft manager Brandon LeBlanc revealed in a blog post that the free support is available to all Vista SP1 users -- regardless of how they acquired the software. "We are offering free-of-charge support to *anyone* who is having issues installing Windows Vista SP1," LeBlanc confirmed.

The move is an apparent response to widespread criticisms from would-be Vista SP1 users who say they can't get the software to install or run on their computers.

"I downloaded it via Windows Update and got a blue screen on the third part of the update," wrote Iggy33 in a comment posted last week on the Vista team blog.

Iggy33 was just one of dozens of posters complaining about Vista Service Pack 1's effect on their PCs. "What a disaster," wrote SeppDietrich of the update. "It exiled all my Nvidia drivers to the Bermuda Triangle."

Other troubles reported by Vista SP1 users ranged from a simple inability to download the software from Microsoft's Windows Update site to sudden spikes in memory usage.

It's not uncommon for major software patches to cause problems when first released. Windows XP Service Pack 1 inflicted numerous glitches on host computers when it shipped in 2002. Microsoft fixed many of the problems with subsequent patches.

Microsoft last week made Vista SP1 widely available for the first time. The update is designed to increase Vista's speed, security, and reliability. But the company has admitted SP1 isn't perfect.

The service pack will not install on computers that use device and system drivers that Microsoft has deemed incompatible. The list includes audio and display drivers made by Realtek and Intel, as well as drivers from several other manufacturers.

Microsoft said it's working to resolve the compatibility issues.