I have an M Audio Fast Track USB interface that I can't use to record through Kristal (my DAW). I know it works because I plug in headphones and can hear my guitar, additionally it works using Revalver Standalone.
That's what I use except the program I use is Adobe Audition. Works great.
Kristal is probably set to record from your soundcard. Set it to record from USB (I think)
echoplex is probably right. I have a fasttrack too, but I use ableton live. Check your audio in and out settings. Choose fasttrack as both.
Set it to record from USB, it acknowledges the Fast Track, just doesn't take input from it i guess. I can still hear my guitar through my headphones so I know the fast track is working.
Try using another DAW. Get audacity if necessary, because it's free and I've used a Fast track type m-audio USB device to record with it.
I'm wondering if maybe running windows 7 has anything to do with it? I'll try on my computer with xp and see if it works there. The DAW that came with it wasn't supported by windows 7 so we'll see if maybe thats the problem