Install download?

I downloaded a trial version of a lasersoft program that had a .sit suffix. The documentation/user download asked for a program to open it. Nothing in the applications looked appoiate so I specified my Word trial program. It didn't open it and set itself (word) as the default application.

When I double clicked the program download on my desktop it tried to use word to open the program instead of running an installer.

I removed the word demo but now when I try to open the demo program it says that no application is specified to open it.

What's up?

I have downloaded other programs nd just double clicking opeded the installer and all was fine.

Boy, do I sound like a Mac newbie!

thanks for any help.

LOL Mattlike! I just got my new iMac about 5 days ago and have been going nuts over this big time. Just hours ago, I learned that 10.4+ doesn't have Stuffit loaded even though, Stuffit is an option in "open in" leading people to believe they have it. Gah! What were they thinking?