How to recover my downloaded UE after the system reinstallation?

I reinstall my operating system and I cant link my unreal engine to the epic launcher now. because I installed the engines on D which means I still save the infomation and resources, but I cant launch any of them. I tried to install a new engine at the same location, but it’s forbidden because a new engine needs an empty directory. Can I use the resources I’ve already downloaded before the reinstallation? Or do I have to reinstall all of them?