I have run a lot of newer games than this and had no issues
Just because a game is newer doesn't mean it's more demanding than an older one. A newer game may also be better optimized, or have more options for playing with low end video cards. You can't go by "newer."
I would like to delete it and reinstall but I downloaded the game from steam and don't have the key.
I don't know what you mean by needing a "key."
You use the "Steam key" to purchase the game at Steam.
After that you shouldn't need the key again. The game should be in your Steam library and available for download.