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You can manually set browser executable in config.ini. Just set the BrowserExecutable= to exe of your browser
Do you have portable version or installed version? Is the systemexplorerservice64.exe running under services ? (as system process)
Very strange..It should work on Win XP. Could you please try some older version from download archive ? http://systemexplorer.net/download-archive
Very strange message. Please try to redownload and reinstall system explorer. It runs on 64bit win7 without problems
No there is no need for uninstall, installer will stop running instance of the System Explorer and keep all settings... Use uninstall/install just for troubleshooting.
Most of users are ok with download. Which browser and operating system do you have? Did you try different browser?
I'm sorry... the message with start /NOSERVICE is still same?