Greg,
For RTTY contesting I recommend N1MM with the MMTTY engine. All free. It's not trivial to configure so read the docs carefully.
The most user friendly is Ham Radio Deluxe with DM 780.
The most widely used program for just general RTTY is probably FLDIGI.
All of these are free but not trivial to configure. If you plan to work the contest this afternoon I recommend you plan at least two hours to get everything configured the first time.
GL and unfortunately I won't have much time for the contest since I have grand kids here for the weekend.
73,
Mack
W4AX