Login Problems
I would suggest deleting coh.checksum in your CoH directory. When running the Updater it should build a new, and check if all your files are ok.
Could be a whole bunch of issues if you're able to log in but not access the servers. I'd really recommended contacting customer support.
Have you tried logging into a different server? Have you tried logging into the test server? Have you tried logging into Virtue with a friends account? Have you tried letting a friend log into your account from a different PC? Trying all of this will help Customer Support pinpoint the problem.
I browsed through Common Solutions thread, but couldn't really find anything that helped. Here's my situation: I was playing for a bit earlier, then I logged out. Tried logging back in and CoX crashed with the "City of Heroes has encountered a problem and needs to close." pop-up. So I close it, start up again, and try to log back in. I click the server and then it crashes again with the same pop-up.
I'm at a loss because when I initially logged out and back in, nothing changed. I hadn't installed anything, changed or updated any settings or anything. Any help?