Yeah, I've read about issues in the past with files left behind after uninstalling preventing or corrupting future installs. Once your wallet files are backed up, uninstall Electrum, and entirely delete the Electrum folder from both AppData\Roaming as well as anything left behind from wherever you installed Electrum (Program Files is the default location on Windows). Once everything is deleted, restart and then install again. I'd also re-download the installer to make sure it wasn't corrupted during download.

Many Electrum logs will report a failure to connect to JSON-RPC servers for a variety of reasons but still work just fine. This error shouldn't stop your client from opening. Can you post your full logs?