Desperate for Help

[RastaPastaYT]

Please excuse any grammar mistakes, they text is too bright to see even highlighted. I'm having major issues with the technic launcher. I've tried reinstalling the launcher and everything else I read on the forums that would help. My problem is that when I was playing a modpack I exited the game and launcher to change a config, as soon as I relaunched it wouldn't load the modpack. I tried everything from relaunching to resarting my system to reinstalling the modpack. I tried deleting the mod pack but when I reinstalled it, it would keep saying install no matter how many times I tried installing it. Same problem happened to a few other modpacks. Changed a config, boom modpack ruined. I went as far as deleting the modpack folder manually but windows would say I couldn't delete all of it because it was "in use" even after I closed the launcher. Please help me, I'm getting fed up with this problem.