Thank you very much for your answer. I have Windows 7.
I have read this solution:
"Hi the Problem is in the registry. Not correct set Permissions. If you are using Win 7, SP 1, you might do the following: Open registry Browse to HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\App Paths\Photoshop.exe May be you want to save it first.... Make a rightclick on Photoshop.exe Permissions Add the current User your are logged in and grant him all permissions you can grant. May also check on extended permission and make sure. You then should be able to install the upgrade. Thats what the support just did with my PC."
I tried to implement it but when I tried to do it the system doesn't permit me. It tell me "access denied".