Every time you insert a USB device such as a USB flash drive, an entry will be inserted into your registry. An excellent program called DriveCleanUp can remove these entries and not only detect USB devices quicker but cleans your registry entries for these storage devices. (MountedDevices)
Once you download DriveCleanUp, unzip (extract) the program and copy the .exe file to c:\Windows\system32.
Right click on the file and Run as Administrator.