arduino Uno r3 issues after working fine

I have an Arduino R3 that was purchased from Amazon, actually it was a present from my wife so I’m not 100% certain where it originated from but it seemed to be in authentic packaging…

It was working fine as I had a program that was communicating with 7 each cascaded 7 Segment displays (the Display LED’s are Powered externally with 12V), a button matrix using 8 IO (rows & columns), and a 16x2 Serial Mono LCD. It is possible I pulled too much through USB power or maybe an IO backfed 12V to something.

Had an issue that caused PC damage (PC is in shop) and I am trying to detrmine what might be wrong with the Uno in parallel on a different PC.

I disconnected everything from UNO, when I connect it to PC, the Green Power LED is lit, and the “L” LED connected to Pin 13 is constantly lit as well.

Step 1: All rails seem to be as expected (5V, 3.3V), nothing seems to be shorted to GND.

Step 2: Using terminal program, the Loop Back Test works fine.

Step 3: When I try to upload Blink, I get the following with verbose:

Binary sketch size: 1,084 bytes (of a 32,256 byte maximum)
C:\Users\rrobbins\arduino-1.0.3-windows\arduino-1.0.3\hardware/tools/avr/bin/avrdude -CC:\Users\rrobbins\arduino-1.0.3-windows\arduino-1.0.3\hardware/tools/avr/etc/avrdude.conf -v -v -v -v -patmega328p -carduino -P\.\COM5 -b115200 -D -Uflash:w:C:\Users\rrobbins\AppData\Local\Temp\build3169906754357257603.tmp\Blink.cpp.hex:i

avrdude: Version 5.11, compiled on Sep 2 2011 at 19:38:36
Copyright (c) 2000-2005 Brian Dean, http://www.bdmicro.com/
Copyright (c) 2007-2009 Joerg Wunsch

System wide configuration file is “C:\Users\rrobbins\arduino-1.0.3-windows\arduino-1.0.3\hardware/tools/avr/etc/avrdude.conf”

Using Port : \.\COM5
Using Programmer : arduino
Overriding Baud Rate : 115200
avrdude: Send: 0 [30] [20]
avrdude: Send: 0 [30] [20]
avrdude: Send: 0 [30] [20]
avrdude: Recv: . [02]
avrdude: stk500_getsync(): not in sync: resp=0x02

avrdude done. Thank you.

Any suggestions with details are appreciatted.

Thanks in advance.