Baldric, what happened just before your legs refused to work? A similar thing happened to me about ten years ago, it happened in the afternoon and I had fallen asleep in a chair. The phone woke me and I tried to stand up but the legs just buckled, managed to get to the phone on my knees. My caller phoned for an ambulance and I had a lot of tests but nothing found. The Doctor eventually said something along the lines that I had been awakened very quickly by the phone call and somehow the brain "forgot" to send the right message to the legs, make of that what you will. It hasn't happened since.