url’s not working

Hello everyone,

Not sure if this is the right topic, but I have no idea where to start looking for my problem.

But since I think today my site is completely broken. I hope you guys want and can help me. Cause my knowledge about this isn’t that great.

So to give you an idea what the problem is:

http://gadgethingy.com NOT working
http://www.gadgethingy.com/ Homepage is working but not any article or other page
http://www.gadgethingy.com/jellytank-aquarium-e22000/ Not working page not found
gadgethingy.com/jellytank-aquarium-e22000/ Not working page not found

Do you maybe have an idea what this could be?
Until yesterday everything worked perfect and didn’t do any changes or haven’t installed any new plugins.

Thank you guys!