My phone is not booting up need urjent help

my phone stucks in charing screen and then again reboots with nokia logo.

Trying soft reset does not help this, we get the Nokia logo then charging screen.

When this is on, if we disconnect the power cable, the phone immediately turns off.

its going in a loops and cant starts up .. it is happening after installing windows 10 peview build 10084 .

i know it can be solved by flashing but the main thing is that i have my contacts and messages and most important 7 gb of important file was present which i need it at any cost ..

is there any way to solve without flashing so that i can get the data or is there any way to recover the data as i need it at any cost please .. help me out soon ...