Users remained stymied today by endless reboots after trying to upgrade their PCs to Windows 7, according to messages posted on Microsoft's support forum.

An answer has yet to be found for all users, who began reporting the problem last Friday after watching the upgrade stall two-thirds of the way through the process. Most users said that their PCs had displayed an error that claimed the upgrade had been unsuccessful and that Vista would be restored. Instead, their PCs again booted to the Windows 7 setup process, failed, then restarted the vicious cycle.

Several Microsoft engineers, including the company's senior group manager for Windows supportability, have offered advice, but on Monday users continued to publish complaints on a growing forum thread.

"I think I've gotten to the point where trying to install Windows 7 is simply not worth it," said "Chimaera717" around 1 p.m. ET today. Chimaera717 was one of the first users to gripe about reboot hell. "I'm more content with actually having a working computer. Anyone know if we can get our money back?"

Earlier, Microsoft support engineers posting to the thread urged users to burn downloaded upgrades -- which were delivered as disk image, or .iso, files -- at their DVD drives' slowest speeds to reduce the chance of corrupting the data, one possible explanation for the endless reboots. At the same time, one user pointed others to a document published last July on Microsoft's support site that spelled out a possible solution.

Late Monday, Paul Aaron, Microsoft's senior group manager for Windows supportability, chimed in with a link to another support document. "From reading through the article, it looks like there is a service running in the background that is preventing the upgrade from completing," Aaron said. "Hope this helps."

The document, published in early September, noted that the "iphlpsvc" service -- which offers IPv6 connectivity over an IPv4 network -- may cause Vista-to-Windows 7 upgrades to hang at the 62%-completed mark. The fix that Aaron highlighted requires users to modify the advanced system settings of the PC.

Those instructions didn't do anything for some users, who said that their systems were still crippled.