Along with a boatload of thread running, something is pounding your drive. Take a look on the Processes tab of Task Manager and sort it by CPU and also by Disk. That should let you figure out what's doing all that activity. Since you mention "in idle," I'd guess it's some background processing for Windows. But, nothing it does should be putting 100% loads on both CPU and disk (I'd have guessed indexing or virus checks -- but I have no actual basis for that).