It could be many things. Are you logging on with a wire or wireless? Have you tried Firefox?
Wireless connection logon, and as for Firefox—Omigosh, you talk about browsers messing up! It kept opening up multiple tabs without my say-so to ad sites, and pop-up add crap everywhere. Could never get anything done, so after two tries of uninstalling and reinstalling and making sure I had the latest version, I finally called it quits. I’m thinking of reinstalling Tor.