can you give some more details on the client not opening? does the client window ever display or does it just never connect to a server and sync/display a transaction history.
if you can get to the preferences options, what are the settings for connecting? Are you trying random servers if the selected one is not available?
Also, what version are you running?
1.8, the latest version for windows.
I deleted everything about Electrum in my AppData folder. Since then everything has been working fine. It was odd, but I'm no longer having problems.