Hey there @emamb4! Welcome to the community! As Nawrot mentioned, this often stems from either your drivers needing to clean reinstalled, your Nvidia settings needing to be defaulted/refreshed, or if your GPU is too old to get newer drivers, you may need to downgrade a project to DX11 to be able to use it. We could definitely give a bit more context knowing your specs however!
Here’s a thread that has a variety of solutions including how to downgrade the project’s RHI if your hardware needs it, as well: