Hello Mr. Alferdo! It is difficult for the PC program to judge by a 0xFF that the uC was reset (perhaps due to some power problem) OR it was some correct data transmitted by the uC.

About clearing the buffer, I have already tried it.....I don't know if I was not doing it right or what......I was calling the PurgeComm (...) function...but things were not working.

Hello Mr. Erik.

Actually when I single step, the first instruction to be executed is a
WriteFile (...) function. It will be executed regardless that I single step OR I just run over it.

The only difference is that the ReadFile is executed a couple of micro-seconds after WriteFile in once case and in the other case there is a considerable delay.

The ReadFile (...) will anyway not return unless it receives something, won't it ?? Or will it just pass over it and return whatever it has in the buffer ??

Regards
Aman