NA/PC, Non-Steam client; Windows 7
This has happened to me twice now.
First time was (spoilers?) while doing the Orsinium story, while helping the Orc get out of the dungeon
Second time was just last night, while in the 'Kennel' delve in Wrothgar.
My character will just randomly stop moving. None of the movement keys work. I can cast spells and do anything else, but they're frozen in place. Can't walk, run, jump, dodge, etc. I have to quit the game and re-launch to fix it. Have tried alt-tabbing out, then back in, which didn't work. Haven't tried a /reloadui, but not sure if that would help.