Incorrect file associations could be the result of underlying issues within your PC system. As such it is highly recommended to scan your PC for invalid registry entries, unused processes and other unfavourable system settings to identify slowdown issues.
The LOO file type is primarily associated with 'Sterlingware' by Stephen Ferguson.
Sterlingware is a fractal program.
Parameter files store the various settings for a particular fractal pattern.
To download Sterlingware you will need to pay a $25 fee to access the download page for all of Stephen Ferguson's fractal programs. (The links here lead to that site.)