Hi Shantanu, erectile dysfuncton can be caused by various reasons such as diabetes, high blood pressure, stress, anxiety or depression, alcohol and tobacco use, brain or spinal cord injuries, stroke etc. You need to consult an urologist to know the exact cause for the problem. Making a few healthy lifestyle changes like quitting smoking, losing excess weight, and increasing physical activity may help you regain sexual function. Psychotherapy and behaviour modifications are considered next if indicated, and ofcourse under specialists supervision followed by oral or locally injected drugs, vacuum devices, and surgically implanted devices. I hope this info will help you. Best regards.