I was previously using this board (sparkfun's version of uno), and it had no issues. But now the windows device manager doesn't recognize the device. Also the power LED and LED 13 flash only briefly when I plug it in to the USB port. If I plug into the barrel jack, both LEDs will light up brightly, but the voltage regulator gets quite hot very quickly. There is also no response from the LEDs when pressing the reset button.
Well, I got my hands on an Uno and it works fine. No hot regulator, connects just fine to my PC, LEDs seem normal...
I'm going to assume that I somehow fried my RedBoard.
Yeah - something failed to a short circuit (or nearly so), so as soon as you connect it to the computer, it powers it for an instant then shuts off power to the port because it's drawing too much current.
Depending on what part failed, it might be possible to fix it (but the usb serial interface may also be dead). Since there's nothing to lose, put it on the barrel jack, and quickly feel around and see which other component is getting hot (and then disconnect it) My money is on either the serial adapter (shitcan it, that's not an easy fix) or the opamp used for buffering pin 13 and doing the power switch (it's easily blown and usually fails to short) - in that case, you could remove that part and either replace it, or hardwire the gate of the power switching fet so it only uses usb power.
No opamp on a RedBoard and it has the FT231XS chip for the communication 
sterretje:
No opamp on a RedBoard and it has the FT231XS chip for the communication
Oh, hm, I'd thought it was a straight up uno clone. Oops.
Well, anyway, my suggestion still holds, it'll just be different part that'll be heating up. I'd be curious to hear what other part was getting hot on barrel connector. That board doesn't have much on it that looks likely to burn out.