I recently reloaded my computer and started over from scratch (spyware issues). Before the reload my Motu was working, but I always has a problem with it whistling. Although the whistling was much less frequent, maybe once every 2 or 3 minutes. I had XP as my operating system with no service packs. I had cubase installed and everything worked just fine, except for the occasional whistling which could have been fixed if I lowered my sample buffer to 128 (which I just did but still it doesn't help my current issue). My motu 828mkII just started whistling every other second on playbacks of any audio/music file. My OS is XP with SP2. The thing is just yesterday I was able to play music files just fine with only the occasional whistle, so SP2 doesn't seem like the issue. When I first noticed the problem it happen after I tried to install Cubase SX and a few VST plugin (which I had installed before) , then all of a sudden I couldn't play any type of sound from my PC with any program. I uninstalled Cubase and the plugin and had the same problem. I also uninstalled SP2 and replaced it with SP1 and the problem still occurs. I also tried some of the tweaks that Sweetwater sent me to optimize my PC for my audio interface, and that didn't work. I also called Motu support and they suggested that it was probably my firewire card (which is in pci bus) or my firewire cable. Or possibly my computer has too many cards installed (because I have a video capture card, the original soundblaster sound card, an ide hard drive controller card, a cable modem card, and then the firewire card) but that doesn't sound right because it was working fine before even with all those cards (and SP2). It seems like the PC & the motu are having a hard time full duplexing during playback. Anyway the strange thing is that I am able to play my keyboard or use my microphone (which are hooked up to my motu) no problem. I am even able to record them and have no problem (meaning no whistling or pauses) with the recorded material. Only when I try to play the material back thru the motu it whistles every other second, but if I play it back thru my sound blaster card the record file plays just fine. I can even play a music file with my windows media player (while it's whistling every other second) and record it with another program (I use cool edit or goldwave) and it records the music file played on the windows media player with no problem and the recording doesn't have all the stops and whistles from the playback that I hear thru windows media player (or whatever program I use to play an audio/music file with. So basicly I want to know what causes my motu to whistle every other second ONLY on playbacks and what can I do to fix it that I haven't already tried? I paid way too much for my equipment to not be able to use it. It's only a year old so I doubt that the equipment is broken, it's probably just a setting or a corrupted driver or something. Speaking about drivers I also uninstalled them and reinstalled and then updated the drivers from v 3.0 to 3.4 (which I downloaded from http://www.motu.com) and the problem still persists. I will try to buy another firewire cable tomorrow and in one last ditch effort try installing my motu on an entirely different computer system. If it works, then I have to go and look about replacing the PCI Firewire card. Unless some of you wonderful folks who knows about this product/issue can help me before it has to come down to that. Please help!!! Originoo Also my PCI Firewire Card is a Texas Instruments card so compatibility shouldn't be an issue... unless it's broken.