Doing a Google search lead me to this forum where I saw this thread: http://forums.bit-tech.net/showthread.php?t=23295 Recently, I built my own computer out of: ASUS P800-E Deluxe MOBO ASUS Radeon 9800 Pro Vid Card RAIDMAX Case Kingston Memory (1 GB) Maxtor 250 GB Hard Drive I already owned the Monitor which is a Sony 19" Multiscan G400. That and the Keyboard and Mouse are hooked into a KVM which are shared with my Mac. When I use the Mac, everything is fine and dandy. However, when I turn on the PC (even if the Mac is off), I get this annoying screeching sound out of the monitor after maybe 30 minutes of use. It can be best described as a high screech, or using a dog whistle that a human can actually hear. At first I thought it was a fan making the noise. I dusted them all, including the VidCard fan and processor fan. I then, one by one, disconnected each fan to see which was the culprit. It finally hit on me that it was coming from the monitor. However, since the sound does not appear when using the Mac, I'm positive it has something to do with the VidCard and Monitor combo. I tried using different resolution settings, which seems to work sometimes, but then the sound eventually comes back. I've also made sure that I am running the latest drivers for everything. The previous thread talked about grounding the Vid Card. Does anyone think that this may have something to do with the sound? Any other info that someone may have to solve this annoyance? Thanks!