The differences between simple paging and virtual memory paging:
In Simple paging, both main memory and process space are divided into number of equal-sized frames. A process may in non-contiguous main memory pages.
But in Virtual memory with paging, same as simple paging but the pages currently needed are in the main memory, known as demand paging. Each process is divided into frames, some of which, though not all, are resident at run time.
In simple paging, all the pages of a process must be in main memory for process to run, unless overlays are used.
But in virtual memory, not all pages of a process need be in main memory frames for the process to run. Pages may be read in as needed.