o when loading up windows press F8. this will take you into some options such as run in safe mode and stuff. firstly DISABLE "restart on windows failure" or something like that (not sure of the exact words), then this should stop your computer automatically restarting in theory i think. anyway now u can get us the error code if one exists OR u can try bootin up in safe mode or the mode where to your last working settings .
hope i helped
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