i start installation Foglight 7.0 (Quest_FoglightPerformanceAnalysisforSQLServer-Client_703.exe) and see strange situation.
Performance monitor display 50% for QI.exe and process monitor display access to HCKR\Installer\Products key.
Installation stay on first screen (license agreement with popup window Extracting files. Please wait...).
For test i install Spotlight without any problem.
I would try executing the installation by right clicking on the file and selecting "Run as Administrator". If that does not work, I'd recommend opening a support ticket via support.quest.com.