Microsoft's Xbox 360, the much-anticipated video game system that made its debut earlier this week, is apparently experiencing some technical glitches -- screens freezing only minutes into a game, for example -- and that has left some users pretty upset.

At gamer-oriented Web sites, Xbox 360 owners have reported system crashes in games such as the space-marines-vs.-aliens title Quake 4.

One owner complained that his new console tries to read the shooter game Perfect Dark Zero as a DVD movie. Another posted a video file of the game Project Gotham Racing 3 freezing up before the player had even finished the first lap of the driving game.

Brian Crecente, who runs the game-fan site, said his Xbox 360 locked up three times, causing him to lose a couple of hours' worth of progress in a Western-themed action game called Gun.

The problems with the gaming console don't appear to be widespread based on feedback from visitors to his Web site, Crecente said, but it's "enough to make me wonder."

Technical glitches are not unheard of in new-game-machine launches -- some early buyers of Sony's PlayStation Portable this spring complained that the device came with dead picture elements on the screen of the handheld game device.

Microsoft played down the number of complaints it has gotten from Xbox 360 users yesterday, saying the company has received only "a few, isolated reports" of Xbox 360 consoles with problems.

"The call rate is well below what you'd expect for a consumer electronics product of this complexity," said Microsoft spokeswoman Molly O'Donnell.

Crecente said the stakes are high for Microsoft's ambitious new console as it aspires to also be a multimedia hub for the living room, connecting wirelessly to the user's home network and a number of other digital gadgets.

"You don't expect your VCR to crash when you hit the eject button," he said.

"Once [a game console] makes the transition from your back bedroom to your living room -- you're on Broadway now. You can't have any misfires."

At Web sites devoted to the new Xbox, some owners were already expressing regret that they had spent up to $400 for the console -- not including games.

"Up until today I was pretty much an Xbox fanboy," wrote one gamer whose online moniker is Kulanose. "But after spending 6 and a half hours outside uncontrollably [shivering] for something that doesn't work right . . . they just lost me and a bunch of people I know."

Over at techno-geek Web site Slashdot, some readers were already trying to diagnose the system's problems from images that had been posted on the Web and come up with their own solutions.

"Let's rename it to crash-box," one visitor wrote.

Microsoft has said it hopes to sell 3 million units of the new game consoles in its first 90 days.

Jose Gonzalez carries the last Xbox 360 from a Circuit City store in El Paso on Tuesday, the day the video game console hit shelves in North America.

Ryan Shaw, 11, clutches his new Xbox 360, which his mother, Martha, bought Tuesday at Best Buy in Pearland, Tex.