I tried deleting the plugin, reinstalling, and entering a new api key. However, I get this message:
The owner of that API Key (username) is not on the access list for this blog (blog id). Stats was installed using a different API key.
Is there anyway I can install the Wordpress.com Stats plugin with a new api key?
Actually, you should be using the JetPack plugin now, not the stats plugin. Automattic (the team behind WordPress.com) have begun bundling their stats system with a few other features (social network sharing, LaTeX support, to name a couple) and aren't updating the older systems any more.
JetPack will use oAuth to connect to your WordPress.com account and will automatically select the right blog. If it doesn't, you should contact their support team directly to ask for help.
Did you try logging into your wordpress.com account, and grabbing your existing API key?
