Microphone is way too sensitive

Recently bought a Tascam TM78 and a Tascam US-100 interface to record acoustic guitar and vocal tracks in the latest version of Audacity (Windows 7). However, every time I start to sing loud at ALL my levels peak; this is especially prevalent on the vocal tracks. I’ve eliminated what I think are all the obvious problems, my input level on the interface is all the way down, I’m using a pop filter, the recording level in my system tray has been lowered (saw almost no difference), I’m not running skype or any other program that could interfere, and I’m absolutely stuck as to why this is happening. As it stands now, I need to be 3-5 feet away from the mic depending on how loud the section is and it makes my takes sound terrible. I tried the microphone in my trial version of FL11 and I seemed to be able to sing directly into it without the levels overpowering everything and peaking. What am I doing wrong in Audacity to cause this oversensitivity? Even my input and mic volumes have been lowered in the program itself and I still can’t stop the levels from peaking.

To clarify, the peaking occurs when I go for a loud take, the mic works (although is still very sensitive) for quieter takes and sections. Does anyone have any suggestions on how I can fix this? Thanks!

Is the “overload” light on the US-100 unit flashing when you sing loudly? If it is then that would indicate that indeed the signal from the microphone is to high for the US-100, which would seem surprising but perhaps you are a really loud singer…

If the “overload” light is not flashing the issue could be a windows driver issue. I’ve seen cases before were the windows driver adds an extra 20 db of gain to inputs that it thinks are “microphones”. (And if you do a google search on the problem you get lots of hits of others with this sort problem.) I my case I cured it by installing the manufacture’s driver for the device instead of the generic windows driver.