When installing the US-122 for the first time, if you experience any unusual behavior, here are some things to check:

Audio Drivers In Control Panel / System / Device Manager (Win98SE/ME) or Control Panel / System / Hardware / Device Manager (Win2000/XP), find the Audio control panel. It’s called Sound, Video And Game Controllers in Win98SE, or Sound & Multimedia in Windows 98/ME and Windows 2000/XP. You should see two entries for the US-122:
• TASCAM US-122
• US-122 WDM Interface
In Control Panel / Multimedia, select the Audio tab. Under Playback, US-122 Out should appear in the drop down menu
Under Recording, US-122 L:R should appear in the drop down menu

MIDI Drivers: In Control Panel / Multimedia, select the MIDI tab. When "Single Instrument" is selected, you should
see:
• US-122
In Control Panel / Multimedia, select the Devices tab. Under Audio Devices, you should see:
• Audio for US-122
Under Midi Devices And Instruments you should see:
• MIDI for US-122.
Expand by clicking on the plus (+) sign and you should see:
• US-122 Port 1
Port 1 corresponds to the US-122’s MIDI I/O ports.