Hi Andrew. Tried that. But in the installation centre, no where and no link for the developer to install a new one. And yes, did back up, but now, the .sql file would not restore. So just had to totally wipe out avg, and do a system restore. As it would not do that. Go back. So, looking for a way to bypass the installation centre, and a msi or .exe to install sql developer, and have a legal copy, as the dream spark, says do not have to have a key, embeeded in the installation. Can you help me out. Or how to install, by pass the set up .exe. A whole heap of msi, which one to install. Or provide me with how to install. My lectuer not back till Monday, which is a pain, looked at different forums, and blogs. Nope, does not let me install, because ihave the express, and did uninstall the express, then no way to install developer, either upgrade assistant or migration wizard, no way to install a stand alone. Can you help. Totally frustrated. Just about to do a system restore back to this morning, unplugged the external drie and flash drive. So. Any help. Marvin.