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The short term memory loss
as well as inability to walk both have their origin from some effect on brain of a person so they are related in this way but short term memory loss does not cause inability to walk.Since it is a sudden symptom that your friend can't walk it is important to get her to a ER or hospital as she will require to get investigated for the cause of inability .It could be a hemorrhage in brain since she is hypertensive;it could be a infarct in brain which is causing this;swelling or atrophy
of brain ;multiple small infarcts .Consult a Neurologist
he will examine and advise treatment for the problem.