Arduino Mega stopped uploading

The Mega was working for about 30 hrs and then abruptly had uploading issues including uploading BLINK.Voltage regulation is good , there is serial port recognition which leaves me with the possibly that there maybe a problem with the Bootloader unless there is something I am missing. What are the chances of a problem developing with the bootloader and what would cause it ? Below is the complete error
. Thanks in advance, Justin

Arduino: 1.8.9 (Windows 7), Board: "Arduino/Genuino Mega or Mega 2560, ATmega2560 (Mega 2560)"
C:\Solar Cookers International\PROTOCOLS - TESTING SOLAR COOKERS\Performance Evaluation Process (PEP)\TESTING STATION - DATA ACQUISITION\Datalogger_temp_wind_sun_rev12b\Datalogger_temp_wind_sun_rev12b.ino: In function 'void setup()':
C:\Solar Cookers International\PROTOCOLS - TESTING SOLAR COOKERS\Performance Evaluation Process (PEP)\TESTING STATION - DATA ACQUISITION\Datalogger_temp_wind_sun_rev12b\Datalogger_temp_wind_sun_rev12b.ino:247:16: warning: invalid conversion from 'const char*' to 'char' [-fpermissive]
record[80] = "";
^
C:\Solar Cookers International\PROTOCOLS - TESTING SOLAR COOKERS\Performance Evaluation Process (PEP)\TESTING STATION - DATA ACQUISITION\Datalogger_temp_wind_sun_rev12b\Datalogger_temp_wind_sun_rev12b.ino:248:15: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings]
nametoken = "";
^
Sketch uses 33248 bytes (13%) of program storage space. Maximum is 253952 bytes.
Global variables use 5850 bytes (71%) of dynamic memory, leaving 2342 bytes for local variables. Maximum is 8192 bytes.
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_getsync(): timeout communicating with programmer
An error occurred while uploading the sketch
This report would have more information with
"Show verbose output during compilation"
option enabled in File -> Preferences.

Make sure you have selected the port of your Arduino board from the Tools > Port menu.

Sometimes the port will be labeled with the board name in the menu. Other times it will not. If you don’t know which port is your Arduino, you can find it like this:

  • Unplug your Arduino board from the computer.
  • Tools > Port
  • Note the ports, if any, listed in the menu.
  • Close the Tools menu
  • Plug your Arduino board into the computer.
  • Tools > Port - The new port listed in the menu is your Arduino board.

Thanks for the reply - did select correct port and also correct device , that was one of the first things I checked .

You could try burning the bootloader. I have no idea what would cause a working bootloader to be damaged, but it's worth a try. You will need an ISP programmer. If you don't own a dedicated ISP programmer, you can use a spare Arduino board as an "Arduino as ISP":