This has been going on as long as I can remember (8+ months) but I rarely use the sound so it wasn't a big deal. However, my kids and I have been using the sound more and it's driving me crazy. It sounds like a dual heartbeat (duh duh) every 17 seconds or so and it jumps up on the mixer as well. It is IDT High Def. Codec. It's on the "speakers and dual headphones"...I've gone through all the sounds under the properties...It is labeled as "windows default (modified)" It sounds similar (but not exact) as the "device connect" and device connect which the .wav on them is windows hardware insert and windows hardward remove. I've used task manager and stopped there is no applications. I've gone into the processes in task manager and stopped everything under my name but didn't want to mess with the system ones. I disabled all startup items and it still happens. I've tried to start in safe mode to see if it happens but the audio is disabled and even when I try to enable, it doesn't let me.