Wow, I've run Inventor 2005 through 2010 on all sorts of PCs and Laptops with problems. However, you may want to clean up your Reg files. If you don't want to go in and do it amnually, use a problem like CCleaner to do it. There could be a file stuck in there that is throwing the installation off. You shouldn't be stuck at the Registration screen unless there is something in the way of a corrupt file that is being routed by the installation process. When you uninstall the program, do a search for remaining related files. It sounds like the problem is with a corrupt file. If it was something bigger (in the way of a problem) you would get installtion error messages while the initial installation screen was up.
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