While opening computer always a dialogue box containing "Windows has encountered a critical problem and will restart in one minute" appears. After appearing this message computer restarted. This is occurring continuously. I have Windows 7.
This will help you out. It has a good answer and seemed to solve the problem. Keep in mind, Windows 7 went out of support so this could be the reason behind this. Since it went out of support, it is more vulnerable to security threats. I would try this out, if it doesn't work then I recommend you go see @Broni, he is very good at malware removal, and may be able to help you out. Or, you can get the newest Windows, and that should solve your problems.