When You install SharePoint 2010 on a server that already has SharePoint 2007 installed on it, it will install all of the 2010 bits on that server in a side-by-side fashion with the 2007 bits. This is a good thing, for all sorts of reasons. However, it can be the source of some confusion, and at least once already in my case, an opportunity for slip ups.
After you run the new SharePoint Products Configuration Wizard (note the new lack of “And Technologies” in the name), you will have converted your farm, which is all of your databases. However, you still have access to all of the code from the 2007 install. This includes the SharePoint Products and Technologies Configuration wizard from the 2007 install.
This can be a real problem, particularly if you have always used a shortcut to run it, and you expect the shortcut to be upgraded. It won’t be… Take care that you’re running the right tool. It’s now installed off the start menu in the “Microsoft SharePoint 2010 Products” folder, and its name is slightly different,“SharePoint 2010 Products Configuration Wizard”. The chrome around it is slightly different,but not enough to tell, but one visual clue that you’ll get while inside the wizard is that the prompt that warns you about services restarting has “v4” in most of the Service names.