Help required for page changing with ST7920-based GLCD

I am a newbie working on an Uno project with a ST7920-based GLCD. The project involves five different display pages (screens). Switching between screens is by means of two pushbuttons SW1 and SW2 (normally HIGH).

I need to switch from screens 1 to 4 sequentially on pressing SW1. This I have been able to accomplish. I also need to jump from any one the first four screens to the fifth screen by pressing SW2. This is where I need help. All my attempts have failed.

For the sake of brevity, I am only attaching the main loop

void loop.doc (31.5 KB)

Please do not attach .DOC files. These are intended for Word Processors

Either copy-paste the complete sketch to a code-window in your message.
Or attach the .INO file (or ZIP up the sketch directory for multi-tab sketches)