HP laptop crashing at startup and restarting again to do the same thing

[kys_sushi]

My laptop keeps on crashing at startup and restarts all over again to crashing again and again. Please help me out, I can't access nor do anything about it as my keyboard doesn't work during the process of startup which means I can't even boot up my laptop in safe mode. 

[Fanordi]

Hello, do you have any message at your screen?? And after few reboots?? 

If you have any message, you can try to reboot taping F11 key, and access to the troubleshoot options. So you can try to restore your PC to a previous state or uninstall last updates. 

If any works you can execute an hardware test in your computer. For this, restart your computer by tapping F2 when it is been down for restart. You come in HP Hardware Diagnostic Interface and can execute all tests. If you have a fail please tell us. 

For more information about HP Hardware Diagnostics please see this: 
https://support.hp.com/us-en/document/c03467259