How do you start up a 3000 n100 Lenovo laptop

Issue could also be a stuck fan.

If you see the lenovo screen at first but it just does not start windows and keeps looping then it is the hard drive.
If you have to keep pressing the power button then it is more likely it is the fan. You can always see if you hear it at the fan vents or under the access pael where the hard drive is.