Apple Computer believes it has a winner with the new iTunes 7, but many users dealing with poor sound quality, sluggish performance and other problems are giving thumbs down to the music and video playing software that also connects to Apple's online store.

The stream of complaints that followed the Tuesday release continued Thursday with no official response coming from the computer maker. Problems listed on Apple discussion forums were posted by PC users, as well as Apple's Mac customers.

People who upgraded to iTunes 7, which Apple had crowed was the "most significant enhancement" since the software's 2001 debut, reported sound distortion, songs skipping, 3-second delays in playing tunes and lost tracks. In addition, some users reported they were unable to download songs from the iTunes store, and could only get audio during video playback.

While other factors, such as a person's computer system or other software, could be responsible in some cases, the hundreds of users posting complaints and responses to problems was an indication fixes may be necessary.

Apple officials were not immediately available for comment.

"The difference between iTunes 6.0.5 and iTunes 7 is frighteningly bad considering the normal iTunes functions have been severely compromised," a user who identified himself as NYC Saint wrote.

"After a day of frustration -- this thing is sooo slow ... This truly sucks," Kpod1 of New York said.

On Thursday, Microsoft released details of Zune, a portable player and online store the software maker hopes will topple Apple's market-dominating iTunes and tightly integrated iPod player. At least one user jokingly made reference to Microsoft's would-be Apple killer.

"Man i thought this was going to be a cool/simple update ... any one heard of the zune ---- !!!! lol (laugh out loud)," digitalmaddog01 of Florida said.

The advice many users gave to avoid the problems was to wait for Apple to release patches for the software.

"Unless it is absolutely necessary for you to upgrade to iTunes 7 right now, I would advise holding off until a correct version is released - these forums are full of members who have spent hours trying to work out fixes - just stick with 6.0.3," Jay said.