Another computer question (please read anyway)

I have software that I downloaded as ISO files from the internet. I'm able to open, extract, and install them, but the computer still insists on having a cdrom in the drive to run the program. Any way around this? Can I just somehow tell the computer to look on the c-drive instead of the disk drive?

Maybe you find something here. I think this is the place:

http://www.daemon-tools.cc/dtcc/announcements.php

I've been using software called Virtual CD to handle such situations.
http://www.virtualcd-online.com/

However. I believe the Daemon Tools that Pappythesailor is pointing to does pretty much the same thing but I haven't tried it.