I assume you are running Windows. There are a couple of ways to go about it. Try this first, double click on a Carrara file. When Windows says it doesnt know what to open it with, it will ask you what you want to open it with. Hit the browse key if necessary. Then browse to the Eovia folder and find the Carrara Exe. Select it, then also check the box that says always use this program for these file types. However, it sounds as if something is amiss with the registry. So the above procedure should work, but for a better solution you might try uninstalling Carrara. Then search the registry and look for all entries for Carrara and Eovia. Delete all these entries then reboot. Then reinstall Carrara and it should work fine. Please keep in mind the usual warnings when working with the registry. Deleting the wrong thing in the registry "can" screw your computer up. However, if you only delete the keys that are related to Eovia or Carrara it shouldnt be a problem. So if everything seems to work fine after doing the first suggestion you might not want to try the second, but as long as you are careful it shouldnt be a problem. Hope this helps. Donnie