Sketch uses 2072 bytes (6%) of program storage space. Maximum is 32256 bytes.
Global variables use 50 bytes (2%) of dynamic memory, leaving 1998 bytes for local variables. Maximum is 2048 bytes.
avrdude: ser_open(): can't open device "\.\COM3": The system cannot find the file specified.
The board was previously working, and I have tried unplugging and replugging it in multiple times. Additionally, the port option is greyed out, and I cannot select anything with it. Any help would be greatly appericiated
Was the +5V side of the power source just connected to the servo or also the Arduino? Having two connected (both wires) power supplies could be really bad.
Try to draw a schematic on paper, or just take a picture of your setup (though that is not very easy for us to see).
What schematic? Most of us won't spend the time doing research for you. If you have a schematic, post it. But "following the schematic" doesn't mean that you did, which is why we ask to see a drawing of how you have connected everything.