Fatal error during installation. Error number 1603

I have a big problem with Trados Studio 2011: installation fails and I have no operational program.My operating system is Windows 7 64 bit English.

First Studio started to get stuck when starting so that the opening window just stayed on for ever without the program opening. I reported the problem to SDL support, and the advice was to uninstall Java and them uninstall and reinstall Studio. I tried to do that, but the installation halted when installing Trados Studio 2011 S2R at stopping services with the error message "Service 'Nalpeiron Licensing Service' could not be stopped. Verify that you have sufficient privileges to stop system services." I retried and then cancelled when that did not help. After rolling back I got the error message "Set-up did not complete. The error is: Package SDL Trados Studio 2011 SP2R could not be installed. Fatal error during installation. Error number 1603."

Can anybody suggest what to do next? I have previously tried to look up instructions for fatal error 1603 in Microsoft knowledge base, to no avail. I ran the program as administrator, so that is not the problem.