You have to do a few things to delete everything and get your disk space. IT DOES NOT REQUIRE FORMATTING! You need to make yourself the owner of all of the files (main folder, subfolders, and files) in the security tab under properties when you right click the directory. You then need to deny/change some of the permissions of the SYSTEM administrator through that same tab. You should be able to delete then. If you hit uninstall it actually should delete 1 of the 3 (about 3 or 4) PSO2 folders that is taking all your space.
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