Worked perfectly 2 wks: now wants disk in D

Running HomeBank on 64-bit Win7. Installed and worked OK for two weeks. Now when I attempt to open, I get a message asking me to insert a disk (DVD/CD) in drive D (the program is resident on C). If I keep clicking on "Cancel," the program loads, but I get a blinking HD icon on the taskbar, which when clicked gives the name of the exe file and "not found." The computer's OK and has been checked for viruses.

I have a lot of records loaded on this program and hope this is simple.