I am 99% sure I figured out what was wrong with my Arduino Nano 3.0:
Initially I thought I fried the FTDI chip as I could power the Arduino externally and have the program work, but my computer wouldn't detect it. When I checked the 5v line when connected to USB only, though, I was only getting ~3v. Then I tried hooking it up to USB while powered externally and surprisingly my computer detected the serial port.
I figure the fuse is what was blocking some voltage from the USB line, and my computer wasn't detecting it because the signals weren't 5v. So, I need to check the fuse. I have an OSEPP Arduino-compatible Nano 3.0 from Fry's electronics. I can't seem to identify the fuse on my board just by looking, and I don't see it in the schematic.
Can someone provide a picture to identify it?