I bought Arduino UNO R3, I'm new so I copied onboard LED blink program and uploaded it first it worked I tried alter some values of delay just to be sure and after that I inserted external LED of other colour in pin 13 and GND it worked but after I copied same program and now its showing error in compiling
as follows
Arduino: 1.8.5 (Windows 10), Board: "Arduino/Genuino Uno"
c:\program files (x86)\arduino\hardware\tools\avr\bin../lib/gcc/avr/4.9.2/../../../../avr/bin/ar.exe: core\wiring_pulse.S.o: No such file or directory
exit status 1
Error compiling for board Arduino/Genuino Uno.
This report would have more information with
"Show verbose output during compilation"
option enabled in File -> Preferences.
One important skill involved in coding is simply paying attention. Had you been paying attention when you posted this you would have read (reading first is most important skill in coding) the line that says this section is for problems with the board itself and not your project. If you had seen that you probably would have posted this in a more appropriate section and you'd be getting more help.
When someone misses something that obvious a lot of people just dismiss them as too dumb and don't try to help. It would benefit you to have this moved to an appropriate place.
Delta_G:
One important skill involved in coding is simply paying attention. Had you been paying attention when you posted this you would have read (reading first is most important skill in coding) the line that says this section is for problems with the board itself and not your project. If you had seen that you probably would have posted this in a more appropriate section and you'd be getting more help.
When someone misses something that obvious a lot of people just dismiss them as too dumb and don't try to help. It would benefit you to have this moved to an appropriate place.
Speaking of people not reading posts - did you read that error he posted?!
The error he posted does not look like a problem with his project or his code, it looks like some bizarre problem with the compiler process. Look at it - the .o file - the output from the compiler (which goes through a few more steps before winding up as part of the binary if applicable) - for a file from the Arduino core is NOT FOUND! How could that file not be found? It gets created a few seconds earlier!
I suspect this is an overly aggressive antivirus program's real-time protection screwing up the build process; lately this has been an extremely common issue - test if it's the problem by turning off the antivirus, and seeing if it works*. If that fixes it, turn the antivirus back on, and consult the documentation for your antivirus program to see how to whitelist programs.