Thanks so much for the advice. I will try these ideas out. My laptop was charging at one point as I was trying to record, and at other times it wasn't. I plan to also call the Samson company and get tech support. Hopefully, that will help as well. If it does, I'll post back about it. Thanks everyone!

I recently had a similar problem and wanted to comment on what the problem was and the solution in my case. Maybe it might help someone. 
 
First off, I got a new PC and rearranged my recording setup. I have a Toneport KB37. When rearranging everything where I decided to put my Toneport KB37 the USB Cable that come with the KB37 was not long enough. So I had a usb midi cable that's about 3 times the length of the cable that was made for use with the KB37. 
 
So I got everything setup, I kept getting pops, clicks, hum, static and my first thought was maybe it was the PC setup or Latency or drivers. It was none of that in my case. 
 
Long story short, I switched back to the shorter cable that came with the KB37 and that completely fixed the problem. 
 
What I had failed to realize or think of when I switched to that really long USB cable was the fact that my Toneport KB37 is powered from the USB Port, it doesn't have an independent power supply, so for whatever reason, possible voltage drop not powering or carrying the signal, using the really long USB Cable was my entire problem.  
 
I even tried using the regular cable and a small usb extension cable only adding about 3 feet extra length and still had the problem, only it was not as bad.
 
So at least in my case switching to the factory length cable that came with the KB37 directly plugged into the USB port solved all of my problems. 
 
Just wanted to mention my situation in case someone else might run into this issue in the future and not think of it. 
 
 

If it is a hissing noise and not a hum, sounds like you have issues in your recording signal chain.  Older equipment with capacitors are notorious for this issue... even though we want to keep vintage gear virgin, re capping is quite often necessary.
 
The other issue can be from lower quality newer audio interfaces (pre amp), same idea where the internal electronics are introducing the noise.  I don't know if anyone mentioned this but is the hiss on the tracks too?  Or just through the monitors?  If just through the monitors, you might want to check out using BALANCED cables for your speakers/mixer (if they accept balanced inputs - which they should).
 
Jim

I would've suggested that perhaps your mic was picking up fan noise, very easy to do with a condenser mic, but I guess having the issue with the mic turned off (is that what you mean by silent?) rules that out.

everybody gave you good advice track down the source. the sonitus fx:gate can work well to gate low level noise on a recorded track.

One more thing to try... that is, if you mute one track at a time and the noise goes away, you know it is related to something in the signal chain of that track.  Sometimes plugins add noise just being on and not set correctly.
 
Jim