Thanks for the reply myst6re and no, i don't have any user name and stuff like that. But no worries myst6re, i've just found out an alternative way to make the game not delete my save game. I use these steps to make edited file playable without being deleted, in case you need it:
1. Edit the save file and save as normal
2. Make a copy of the save you just edited to somewhere else.
3. After the intro square soft, square enix, the edited save file will be deleted.
4. Alt + tab out of the game, copy the save in step 2 to the "%USERPROFILE%\Documents\Square Enix\FINAL FANTASY VIII Steam".
5. PLAY the edited save file.