Why is windows 10 not working properly on my laptop?

My processor is 2.5Ghz core i5. Ram is 4 gb. I upgraded from win 7. Now it doesn't work right. Some time the laptop goes crazy. Cortana isn't responding. Sometimes the Keyboard and touchpad arent responding. The interface looks nice though. Help!

Added (1). Its a 2nd Gen Lenovo

Once W10 has finished the installation and you are logged in and on the Desktop screen, locate the HDD light. You will notice the light to be illuminated or blinking. Windows is now configuring the installation. Allow the system to run unimpeded until the light stops flashing. If the unit is not equipped with a HDD light, allow the system to run unimpeded for at least one to two hours. You will run into issues if you do not allow for configuration such as programs not working correctly or sound issues.

Restart & enjoy…

Lenovo ram 8 gb 1 tb hard disc i'm using windowes 10 upgraded… Strucking videos and frequently asking restar the computer and sometimes ear phones are not working again restart the system then it workes please solve my problem

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