Login session is broken, Help

[status-afk]

Hi, My problem is login page, its like when i turn on my laptop, it shows black thing, and the only way to log in is by holding turn off button and slide that thing. But the real problem is, when i lock my laptop, it shows the clock on background and i cant go into that password typing place, it just flickers that place and goes back. And the only way to get back is restarting