I recently got a UNO r3 board(I'm new to all this), and I was able to get it working with the L (Pin 13) LED flashing, and I uploaded the Blink Sketch and was able to change the delay, etc. That worked last night when I used it last. And this morning when I tried to start coding for my Christmas Light Show, the L (Pin 13) LED was on(not blinking) and the TX and RX lights were alternating. I unplugged and replugged, leading to the L LED still staying on not blinking (the TX and RW are off) and I can not upload anything to it, but it is still "Working properly" according to the stats on my Windows PC. Please help.