Please DETAIL exactly what cables you have running into and out of the audio interface.

Also, please detail the settings on the front panel knobs and buttons.

Bob Bone

In particular, (from the manual):

9. Input/Playback Mix Level Knob (Mix IN, PB) – This knob controls the audio mix sent to the Line Outputs, fading between the 
input signals (input monitoring) and the output signal from your audio application software. When turned fully counter-clockwise 
(IN position), only the input signals are heard at the line outputs. When turned fully clockwise (PB position), only the output signal 
from your DAW software is heard at the line outputs.

10. Output Level Knob (Output Level) – This knob controls the signal level at the line outputs. This control is independent from the 
Level knob (14).

11. A/B Monitor Selector Button (A/B) – This switch selects the output source sent to the Level knob (14). In the A (out) position, the main line output signal is sent to the headphone outputs. In the B (in) position, the signal assigned to the S/PDIF output is sent 
to the headphone outputs.

13. Power Indicator LED (Power) – This LED lights when the Power switch (16) is activated, with the unit receiving power from either 
the host computer’s USB bus, or from the (optional) external power supply.

14. Headphone Output Level Knob (Level) – This knob controls the output level to the Headphone output (15). It is independent of 
the main Output Level control knob (10).

Bob Bone

Here is the link to the user manual for your Fast Track Pro:

http://www.ee.bgu.ac.il/~acl/Equip/FastTrackPro_hero.pdf

Bob Bone

I have the USB out going to the USB port on the front of my pc, and I have the guitar jack plugged into the inst line jack on the left labeled "1". The instrument line is selected on. The gain knob is is at 1/3. On the front-right of the interface I have the mono sound on, Output knob at 1/4, Mix knob at 1/2, and level knob set at 2/3. 48V power is on. The speakers I'm using are plugged into the headphones jack on the front of my PC tower. That's about as detailed as I can get, I hope that was enough info (and not too much). Thanks!

A/B button is NOT depressed. Forgot that.

doclightXIX

...The speakers I'm using are plugged into the headphones jack on the front of my PC tower...

When I said that your audio interface replaces your existing inbuilt soundcard, I meant it literally and absolutely.  Connect your speakers to the Fasttrack.

Yep, did that and I still hear nothing.

Just as another piece of info, I have ASIO as my selected driver mode, with my fasttrack selected as in's and out's. No other devices are selected. Just thinking out loud here, but would matter if I was plugging my speakers into the headphones jack on my fasttrack or actually plugging them into the (red/white) output jacks on the back? There are also TRS output jacks on the back and have no idea what that may mean. Currently I have only plugged my speakers into the headphones jack on the fasttrack and into the PC headphones jack.

Okay, so I did hook up my speakers to the TRS output jack on the fasttrack and viola! Sound played through my speakers from my guitar! I have a few more questions but I'll save those for later. Thank you thank you thank you all!

  What speakers do you have? I would use the RCA or the TSR outputs 1 and 2 on the back. If you have powered speakers this will work if not you will need a power amp.

It would be hard to use the headphones out on the front unless you have a stereo phone plug with it split left and right going with two separate plugs for the inputs of your speakers.