It was probably a network problem around 9:15 EST. A quick fix after a few minutes of failure to load TWS is to Ctrl-Alt-Del to bring up the Windows Taskmanager (or run, taskmgr) and End Task the TWS or JVM application and then start TWS over again; repeat if necessary. It was probably not a configuration problem as many people had the same. It doesn't hurt to backup your C:\TWS folder as well. A quicker way is to use Winrar or Winzip or 7zip (free) and compress the entire folder and back it up onto a flash drive as a single file; you could probably do this every week. This is assuming you are using Windows. There are similar procedures to end tasks in Mac and Linux.
Thanks for all the replies. I've had the same problem on 2 different PCs, so I don't think it was a problem on my end. Very strange.
Do you use the "store settings on server" option? I don't and am not sure what I would be saving there but would that explain why it could happen on two different PCs. I also don't know when it saves the settings there. It might actually be worth talking to IB CS about this rather than us. (I've logged in twice today once web based and once with my local tws without any odd issues)