Hmmm... there can be a lot of reasons why your eclipse-orion isn't working.
Try these methods out, at least one of them should work :
A. Removing the .metadata folder in your local workspace helps . It contains a .LOCK file that if not properly closed, prevents eclipse from starting properly.
If you are using a Unix based systems you can type following on command line;
rm -r workspace/.metadata
Then launch your eclipse again.
If you are still getting the loading screen try using a different account, at least that way you'll know if it's an issue with your account or not.
But be warned the above method will remove all your workplace configurations!
B. Try using a dev-tool command to clear the cache :
Open the Dev-tools & run localStorage.clear() in the console.
Hope this helps.