PM2.5 laser dust sensor Arduino serialReadPMValue.h Problem

I have downloaded the Demo for the PM 2.5 Arduino code and the serialReadPMValue.h library. I have installed the library, but when I compile the Arduino file I get an error message - the serialReadPMValue.h file is not a valid library file or is not found? Tried using UNO and Mega boards. Any help/suggestion most welcome
2015-07-20 19:34:18 Hi Parrett,
It;s not a hard problem , and I think these steps could help!
1 Close the Arduino IDE, and try to upload the demo again. If you have never done this before.
2 Are there wires on TX,RX_Pin0,1(Uno) , please unplug them before uploading any sketch.
3which board you use Uno/ Mega? Try as the recommend saying.
Hope to get your any prograss.
Leff
It;s not a hard problem , and I think these steps could help!
1 Close the Arduino IDE, and try to upload the demo again. If you have never done this before.
2 Are there wires on TX,RX_Pin0,1(Uno) , please unplug them before uploading any sketch.
3which board you use Uno/ Mega? Try as the recommend saying.
Hope to get your any prograss.
