Every minute or so my computer is playing the "Windows Logon" alert sound (that's my best guess when I went through and sampled the alert sounds). The sound is very similar to that of a flashdrive being unplugged (and no, it isn't being caused by a flashdrive). I can't find any obvious reason why it's doing this, there are no warning boxes, the action center is empty, and nothing else seems to be malfunctioning. The chime begins immediately upon booting up and it happens no matter what I'm doing, though it seems much more frequent when I'm actively using sounds/music/etc as opposed to just typing or other normally silent activities.
I'm running a HP tx2500z laptop approx. 1 year old. I just formatted the hard drive and installed Ubuntu 9.04 and the WIndows RC yesterday.
Sorry, I can't tell exactly what sound card I'm using; the "Sound" window in the control panel lists it as "Digital Audio (S/PDIF)" and "High Quality Audio Device" with the manufacturer listed as Microsoft.