Inspiron 2350, Windows10, infinite restart loop

Hi

1. I m facing issue with system boot up showing blue screen with text " Your PC ran into a problem and requires a restart..we will restart for you...." .stop code - WDF_Violation..
2. If I happen to press f12 while booting the machine, click on DELL back and recovery (Check Diagnostics - all tests passed successfully)

• Your PC needs to be reparied
• Required device is not connected or accessible
• Press Enter /F8 (but nothing happens even after hitting Enter/F8)

Please help as I m unable to get onto troubleshooting /install OS from external drive /neither get onto command prompt for installing.

Thanks

Nithya