it's a registry issue...
when you try to start without the DVD in something in the registry is telling the prog to look in Drive "X", (where "X" is your DVD drive letter)
When the DVD is in the drive it finds the files, when is isn't in it doesn't.
You MIGHT be able to get round this by searching in the registry for the relevant entry and changing it to show the correct path, (which is now somewher on you HDD)
If you do attempt this back up your registry first!!
Don't attempt it if you don't know what you're doing !
(This problem has occurred because you didn't actually re-install the programme. Generally the method you've used is not one that is recommended, or usually works at all!)