Recently my Dell Studio 1550 laptop running Windows 7 x64 has started having problems with USB devices. I have two devices I typically connect: a Western Digital external HD and a SanDisk compact flash reader. Up until a few days ago, I could have both connected and they operated normally. Now, when I try connect both whichever is the SECOND device plugged in fails in a variety of ways. The order does not matter; the first device works and the second device always fails. The error message is usually "Windows does not recognize this USB device." or "Device driver software was not successfully installed." Sometimes it will appear under "My Computer" but attempts to access it cause Windows Explorer to hang. Anyone have an idea about what could be wrong?