The latest outage occurred overnight, with the main Web page, WinMeSweeps.com, accessible, but none of the links for entering the sweepstakes functional. Though the site was up for a time Friday morning, problems have continued, making entering the sweepstakes virtually impossible. At midday Friday, the site could not be accessed at all.
Windows Me product manager Art Pettigrue acknowledged there have been some problems.
"We have acknowledged there are some issues with the site right now, and we are looking into it," he said.
The promotion is yet another effort by Microsoft to drum up interest in Windows Me, its consumer upgrade to Windows 95 and 98. Microsoft earlier this month said it would offer the upgrade version at an introductory price of $59. Earlier Windows 95 and 98 versions sold for street prices of $89.
Through the sweepstakes, Microsoft is offering 50 boxed copies of Windows Me each day and a grand-prize trip to the company's Redmond, Wash., headquarters. Pettigrue said consumers need enter only once to win, and that winners would receive their Windows Me copies around Sept. 1, two weeks before the software goes on sale in stores. The sweepstakes ends Aug. 31.
Earlier in the week, Microsoft took the site offline and put up a message saying, "Due to technical difficulties with the WinMe Sweepstakes site, we are not currently accepting registrations. Please check back often, as we are working to remedy the issue."
Pettigrue said he did not "know exactly what the issues are. We have been working to try and figure out what the exact problem is."
CNET News.com received numerous reader complaints about the site this week. "What good is a contest you can't sign up for?" asked one reader.
Hundreds of frustrated Web surfers trying to register to win a copy "are getting nowhere fast," said another. "Is it popularity or just a poor server? Either way it may spell more bad feelings for consumers."
While Pettigrue said the response to the sweepstakes has been "overwhelming" and has exceeded expectations, market researcher PC Data said site traffic is not enough to account for Microsoft's problems.
"For sweepstakes sites, the numbers are very low," PC Data analyst Jarad Smith said.
PC Data started tracking traffic to the site after the promotion started July 25. For the week of July 29, the site had 291,000 unique visitors. The following two weeks, Aug. 5 and 12, the site had 307,000 and 299,000 unique visitors, respectively. This week's traffic data won't be available until tomorrow.
The WinMe Sweepstakes site came in at No. 37 for sweepstakes sites last week.
"There are a lot of sweepstakes Web sites out there getting a lot of traffic above and beyond what that site is currently getting," Smith said.
A search of Network Solutions' Whois database revealed that shareware giant Tucows, and not Microsoft, owns the domain name for the sweepstakes site, WinMeSweeps.com. But upon further investigation, this turned out to be an error.
Tucows is also a domain registrar, and Network Solutions' Whois database had incorrectly identified the registrant.
Tucows spokeswoman Charmaine D'Silva said Chicago-based Communicator Marketing registered the WinMeSweeps.com domain through her company July 6.
Communicator Marketing, whose Web site lists Microsoft as a client, did not return phone calls seeking comment.
Pettigrue brushed off any suggestion that Communicator Marketing was the problem.
"A lot of things we do, we work with our partners on," he said. "But that's essentially irrelevant."
Windows Me should not be confused with Windows 2000, which offers more robust networking and portable features and is geared to corporate users.