simulation problem with proteus

[shadyusef]

i face problem with simulation in proteus
i got wrong output not the expected from the written program but i dont know why ?!

while(1){
	start :
	temp = temp_sensor_func();	// call temp sensor function
	dtostrf(temp, 1, 2, buffer); //convert temp value from double to char to display on LCD and transmit with Uart
	lcd_print(&Lcd , buffer);		//display on Lcd 
	_delay_ms(100);					//delay to hold the data on Lcd
	//lcd_clr(&Lcd);
	
	if (temp >37.8||UART_recieve1(&Uart)=='c')			//condtion to check if val is normal or out of range
	{
	lcd_print(&Lcd , buffer);	//display temp on lcd 
	lcd_clr(&Lcd);				//clr lcd 
	UART_transmit_string1(&Uart ,buffer);
		_delay_ms(1000);//send temp to the App
		}//if		
	
	
goto start;	
}// for while
}//for main

this code should display the temp value and send it if it out of range >37.8 or if it receives 'c' char
this code works normaly
but if i change the range from normal to out of range Ex40) it doesn't send or display the temp unless i send 'c' char to continue the code
some thing goes wrong but i cant specify if it from proteus or some thing wrong with the code
kindly i need your help
regards
thanks advance