My windows 7 keep me logging on. when going to logon screen i type the password then after that it will turn to black screen after 3-5seconds it will go back to log-on screen pleaaaaaass help.. then i tried to safe mode then install malwarebytes i detected 1 virus. i think. then i delet it and it restarted but nothing happens..

There is a good chance your PC is still infected. Follow this guide and post a new topic in the malware removal forum requesting help. If you're given the all-clear and you still have problems, let me know here and we'll figure it out.