I've installed Windows 7 x64 over a previous pre-release version. What typically happens is that if you choose not to format it moves everything in existing Windows folders (Program Files, Users etc) into a folder called Windows.old. Then it creates new Windows folders and assigns Admin/System/TrustedInstaller permissions to them so that a regular user can't go about messing with system files/installed applications.
I've done this several times before with previous versions but with version 7600 I've encountered a problem that prevents me from deleting/changing anything in those folders even though I'm an Administrator.
Eg. If I try to remove something from the Program Files folder, it tells me I need permissions from Trusted Installer.
If I change the owner of the file, I still get the error "You require permissions from [owner]". It definitely seems like a bug because even if I make myself the owner, I still get the error. I've found one way around this by removing inherited permissions, changing the owner and permissions and propagating the changes down to all the children (starting at the root). Sometimes it works for groups of folders, other times I have to do it individually per file. Either way, I don't think it's a good workaround because it requires me to make permission changes to entire folders, rather than just the files I wish to edit/remove.
Does anyone know of a fix to this problem?
[edit: Installing "over" a previous version is not the same as an "upgrade". None of your system settings/applications are preserved.]