installation failure winx6412102

I was trying to install Oracle 12c 12.1.0.2 on Windows 7 x64 yesterday and the installer got hung already in the phase of determining the hardware environment (as it seemed to me). It took at least half an hour and still the installer did not return to some prompt. A second time I started without giving the Oracle account login information since I initially thought it being a network problem. The second time with even onger waiting, it got back with an alert box:

This is the end of the log file:

INFO: Redirecting to route <matched>.
INFO: Waiting for completion of background operations
INFO: Completed background operations
INFO: Executing action at state supportedOSCheck
INFO: Completed executing action at state <supportedOSCheck>
INFO: Waiting for completion of background operations
INFO: Completed background operations
INFO: Moved to state <supportedOSCheck>
INFO: Waiting for completion of background operations
INFO: Completed background operations
INFO: Validating view at state <supportedOSCheck>
INFO: Completed validating view at state <supportedOSCheck>
INFO: Validating state <supportedOSCheck>
INFO: Verifying target environment...
INFO: Checking whether the IP address of the localhost could be determined...
INFO: Pause Installationsprogramm von Oracle Database 12c Release 1
INFO: Resume Installationsprogramm von Oracle Database 12c Release 1
INFO: Adding ExitStatus USER_CANCELLED_INSTALL to the exit status set
INFO: Completed