I turned on my P.C as usual and was chatting to a friend on steam, when all of a sudden half way through a sentence my keyboard changed languages. I don't know what language it changed to but most keys were disabled. My onscreen keyboard was also playing up. Everything I could find in the control area was set correctly. There didn't seem to be anything that I could see through task manager either in case there was suspicious behavior. I ran a full system scan using Avast and nothing was found. Any ideas on what it could have been?. My keyboard fixed itself after twenty minutes or so.
Edit: My keyboards a tatty old alienware tactx