Sms display via VGA using arduiono uno r3 and gsm sim900A

Hello,
I have read the thread by Nick Gammon to output on vga from uno r3. I had successfully compiled the code and it works fine(after a few modifications). and then i modified the code and added the gsm commands and other stuff(using the code to display messages from gsm module to 16x4 LCD) so that I could display the message received by gsm sim900 onto the vga monitor . It compiled well but it failed to display.
I think I may have made something wrong with the code that includes message commands from gsm. Please help me with the coding thing.
Here is the sketch.Kindly guide me.Thanks in advance.

screenFont.h (12.8 KB)

TimerHelpers.h (6.92 KB)

work.ino (10.5 KB)

I think I may have made something wrong with the code that includes message commands from gsm.

Does it display data to the serial port correctly?

Thanks for the reply

No,it doesn't.Whenever I add the serial.begin command there is no vga output.

I also tried using the software serial library to use different pins for communication but of no use

Is there any way to receive the message from gsm sim 900 and display it onto vga.

PaulS:
Does it display data to the serial port correctly?

I'm using a single Arduino Uno.

First I added serial.begin(9600) command and checked the vga output.It was distorted.It could display only the first two lines.So,I think there is something wrong with using the serial communication