Ah, Control Panel... PC... :\
Well, you can try to do a search for uninstall programs. People actually make separate programs designed specifically to locate and uninstall programs on your computer, and they are frequently freeware, so you could access them without paying somebody. I have one for my computer, which I believe is called Sponge, but I'm not sure if it's made for Windows or not.
Anyway, you can try manually uninstalling the program, but the reason I suggest an uninstaller is because it should remove all program files. Since you used an installer to add whatever mod pack you added, you don't know where the mod files are, and you'll have difficulty removing them all manually. You can of course root through your PC's program files folder for anything minecraft and remove it, although you will want to locate your saved worlds and keep them somewhere so you can drop them back in when you reinstall.
If you can't find a program for it, try the manual uninstall. You could probably find a tutorial on youtube on how to uninstall programs on your computer.
Alternatively, you could boot up a backup drive and restore your computer to the last time minecraft worked. If you have a backup drive anyway, which you should. <object class="emojione" data="
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