I have the exact same problem.
I have the same problem on Windows 7. I have a drive (on a mirror raid) which has a folder with about 1000 .wav files (most of them recorded from vinyl by me). Whenever I open this directory I see the Windows 7 green bar at the top indicating that explorer is processing or discovering contents, but it never completes. I've left it running for hours. During this time explorer.exe is at or near 100%, and occasionally sharing most of my CPU with dllhost.exe. I can't even play any of these audio files; can't move them. Nothing. I've tried moving a few files to a different folder on a different drive (while in XP - different drive) and the same thing happened. Even with just a handful of wav files.
I'm using Windows 7 (32 bit) installed on a 128GB SSD. I've tried moving the wav files to that drive as well, but run into the same issue. I disabled indexing of files, and don't have SyncToy (as far as I know). I'm using the latest version of NOD32 Anti Virus. Btw, if I try to access this folder using a different program, such as the Ableton Live music software, I can search, play, etc. without any problems. Its super fast.
I've tried repairing the W7 installation, and a few other suggestions found on the web but nothing worked. I'm basically ready to give up on Windows 7 and keep using my old XP installation. In XP the folder works fine.
Any ideas or suggestions as most welcome. Thanks.