My lenovo laptop does not turn on?

When switched on lenovo logo appears and it freezes
when i press onn and off button continuosly and turn it on and off multiple times it is then that it turns on after about 30 mins. And then laptop functions properly

When you get it turned on properly again, back up your data to an external drive. Chances are one of the hardware is failing and it's struggling to power up. I have seen this happened a few times with my own computers.

If your laptop is still in warranty, ask for help from Lenovo tech support.