find your STEAM (presumably) directory. usually C:\Program Files (x86)\Steam then go further. C:\Program Files (x86)\Steam\SteamApps\common your 5678 game should be in a folder called Baldur's Gate or some such.
Do you have other mods installed, and do you have any crashes on the clean install?
Flirt Pack is a relatively harmless mod - it just adds "dialogue on click" for the romance interests. That's why I'm surprised - usually I don't foresee any trouble, especially since it didn't need many adjustments for BG2EE.