There is a programme which allows users to play traditional pen and paper roleplaying games with the rule sets like D&D and Call of Cthulhu, that is called
Fantasy Grounds.
Usually you need 3-6 players, and depending on who is playing each person will need to purchase a lite version which is around $20. Its a really nice, mature, programme, with a thriving forum and brings back good memories plus great for new players of rpgs that cannot find local groups.
There is a demo available so be sure to run that to make sure it works first and msg me back here on this thread if you have decided to play with the software.
Cheers, have a great Day.
Axel.