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MagicAndre: Thank you very much for this post. I had a very similar problem and used your instructions to identify the problem. In my case, Win7 automatically updated a driver for an I/O card and there were conflicts with the IRQ's. I had suspected the driver update as it occurred about the same time that I noticed the high (30%) CPU usage. But I had no idea how to check or confirm until reading your post. Vielen Dank! Tim