When I listen to music files on my brand-new PC the speed of playback varies. If you're old enough to remember what a record player is, it's just as if someone put their hand on the turntable to slow it down. The sluggishness lasts for just a few seconds. The files are okay -- they played fine on my old computer. To be sure about that, however, I burned one of the problem songs onto a CD, which I then played back on a CD player; there was no problem at all, so it's clear to me that something is awry inside the black box. Any suggestions would be appreciated, so that when I go back to the vendor I'll sound clever!